DAY – 21 : Insta 75 Days Revision Plan-2025 : SCIENCE & TECHNOLOGY

Solution: B

The Yaounde Declaration (2024) represents a renewed push against specific neglected tropical diseases.

Option (a): Incorrect: While Malaria is a major issue in Africa, the Yaounde Declaration specifically targets certain Neglected Tropical Diseases (NTDs). The Abuja Declaration is more associated with Malaria.

Option (b): Correct: The 2024 Yaounde Declaration specifically centers on reaffirming commitment and accelerating efforts towards the elimination of Human African Trypanosomiasis (HAT), commonly known as sleeping sickness, particularly focusing on the gambiense form. It builds upon previous efforts and aims for elimination as a public health problem.

Option (c): Incorrect: Tuberculosis, especially drug-resistant TB, is a major global health challenge addressed by various WHO strategies and national programs, but it is not the primary focus of the 2024 Yaounde Declaration.

Option (d): Incorrect: Polio eradication is governed by the Global Polio Eradication Initiative (GPEI) and related declarations/strategies, distinct from the Yaounde Declaration’s focus.

Solution: B

Small Modular Reactors (SMRs) represent a newer generation of nuclear reactor designs, typically smaller in size (up to 300 MWe) and designed for factory fabrication and modular deployment. India is actively exploring SMR technology.

While India has a long-term interest in Thorium, the initial SMR designs being actively considered or developed globally, and likely for India’s near-term deployment (“Bharat SMRs”), are predominantly based on established Pressurized Water Reactor (PWR) technology using Uranium fuel. Thorium utilization might be a future possibility but isn’t the primary basis for current SMR development focus.

Hence, statement 1 is incorrect.

SMRs’ smaller size, modularity, and potentially lower infrastructure requirements (cooling water, grid connection strength) make them suitable candidates for powering remote industrial sites, off-grid communities, or replacing aging fossil fuel plants in areas with weaker grids, compared to large conventional reactors.

Hence, statement 2 is correct.

Enhanced safety is a major design goal for SMRs. Many designs incorporate passive safety features that rely on natural forces like gravity, natural convection, and pressure differentials to manage reactor shutdown and cooling during off-normal events, without needing operator action or external power sources (like diesel generators) for extended periods.

Hence, statement 3 is correct.

Solution: A

Nonylphenol Ethoxylates (NPEs) are non-ionic surfactants used in various applications. Their environmental breakdown leads to Nonylphenol (NP), a compound raising significant environmental and health concerns.

• Statement 1: Incorrect: While NPEs are surfactants used in detergents, industrial cleaners, and other applications, they are not readily biodegradable. Their degradation often results in the more persistent and toxic Nonylphenol (NP). Their use in household products is restricted or banned in many regions (like the EU) due to these concerns.
• Statement 2: Correct: Nonylphenol (NP) is well-documented as an endocrine-disrupting chemical (EDC). It can interfere with the hormonal system, particularly by mimicking estrogen. It is also known for its persistence in the environment, especially in aquatic ecosystems, and its tendency to bioaccumulate.

Statement 3: Incorrect. While there are BIS standards (e.g., IS 11704) restricting NPEs in detergents intended for household use, and growing awareness, India has not implemented a complete phase-out across all industrial and consumer applications. NPEs are still used in various industrial sectors like textiles, paints, pesticides, etc. Regulation is less stringent compared to regions like the EU.

Solution: C

Nafithromycin is a semi-synthetic antibiotic developed to combat bacterial respiratory tract infections, particularly in the face of rising antibiotic resistance.

• Option (a): Incorrect: Antibiotics, including Nafithromycin, target bacteria. Antiviral drugs are used for viral infections. No single drug effectively serves both purposes in this manner.
• Option (b): Incorrect: While marine microorganisms are a source of novel compounds, Nafithromycin is derived from erythromycin A (a macrolide) and belongs to the ketolide class (specifically, a lactone-fused ketolide), not a completely new class from marine sources in this context. Its activity spectrum focuses mainly on respiratory pathogens, not necessarily broad XDR bacteria.
• Option (c): Correct: Nafithromycin is a next-generation antibiotic structurally related to macrolides and ketolides. It has shown high potency against key causative agents of Community-Acquired Bacterial Pneumonia (CABP), such as Streptococcus pneumoniae, Haemophilus influenzae, and atypical pathogens. Crucially, it retains activity against many strains that have developed resistance to older macrolides (like erythromycin, azithromycin). Its pharmacokinetic profile suggests potential for shorter treatment courses or less frequent dosing compared to some older antibiotics.

Option (d): Incorrect: Nafithromycin, like other macrolides and ketolides, functions by inhibiting bacterial protein synthesis by binding to the 50S ribosomal subunit. It does not primarily inhibit DNA replication (which is the mechanism of quinolones).

Solution: A

The Widal test is a serological assay historically used for the diagnosis of typhoid (enteric) fever, caused by specific Salmonella serotypes. Its utility and interpretation have limitations.

• Statement 1: Incorrect: The Widal test detects antibodies (agglutinins like anti-O and anti-H) produced by the patient’s immune system against specific antigens of Salmonella Typhi and Paratyphi. It does not directly detect the bacteria themselves. Blood culture is used for direct detection.
• Statement 2: Incorrect: A single positive test is often inconclusive. Antibody titres can remain elevated from past infections or vaccinations. Also, in endemic areas, baseline titres may be present in healthy individuals. A rising titre in paired sera (samples taken days apart) is more indicative, but even that has limitations (false positives/negatives). Clinical correlation is crucial.

Statement 3: Correct: This describes the principle of the test. Patient serum (containing potential antibodies) is mixed with preparations of killed Salmonella bacteria containing specific O (somatic) and H (flagellar) antigens. If specific antibodies are present, they bind to the antigens, causing the bacterial cells to clump or agglutinate, which is visible.

Solution: C

Fog Computing, often used interchangeably with Edge Computing or as a specific layer within it, is an architectural paradigm addressing the limitations of traditional cloud computing for certain applications, especially those involving the Internet of Things (IoT).

• Option (a): Incorrect: Fog Computing is complementary to, not a replacement for, Cloud Computing. The Cloud still offers large-scale storage and complex processing capabilities. Fog handles intermediate tasks.
• Option (b): Incorrect: While Fog computing involves processing closer to the edge, it’s not exclusively on the end-user devices. It implies an intermediary infrastructure (fog nodes) which could be routers, gateways, or local servers, sitting between the edge devices and the central cloud. Processing solely on end devices is closer to pure ‘edge’ processing.
• Option (c): Correct: This accurately describes Fog Computing’s role. It extends cloud capabilities closer to the data sources (edge devices/sensors). By performing initial data processing, analysis, and storage locally or regionally (in the ‘fog’), it reduces the amount of data sent to the central cloud, thereby lowering latency (crucial for real-time control systems, autonomous vehicles, etc.) and conserving network bandwidth.
• Option (d): Incorrect: Fog Computing is specifically designed to address latency sensitivity, making it suitable for real-time interactions and IoT applications, contrasting with batch processing where latency is less critical.

Solution: C

TRISHNA is an upcoming Earth observation satellite mission jointly developed by the Indian Space Research Organisation (ISRO) and the French Space Agency (CNES). It focuses on observing Earth’s surface in the thermal infrared spectrum.

• Option (a): Incorrect: While aerosols can affect thermal measurements, the primary goal is not aerosol mapping. Missions like INSAT-3DR/3DS or dedicated air quality satellites focus on aerosols.
• Option (b): Incorrect: Sea surface salinity is measured using microwave radiometers (like on SMOS or SMAP missions), and ocean currents are often tracked using altimetry and other methods. TRISHNA’s focus is thermal infrared.
• Option (c): Correct: TRISHNA’s core objective is to acquire high spatial and temporal resolution imagery of Earth’s surface temperature and emissivity. This data is crucial for monitoring evapotranspiration rates, water stress in crops, soil moisture estimation, urban heat island effects, detecting subsurface fires, and managing water resources more effectively – key aspects of natural resource assessment, agriculture, and climate monitoring.

Option (d): Incorrect: While thermal anomalies can sometimes indicate geological activity, TRISHNA’s instrumentation and orbit are optimized for surface temperature monitoring related to water and vegetation dynamics, not deep geological exploration which often uses different remote sensing techniques (like radar or hyperspectral imaging) or ground-based methods.

Solution: B

The NIDHI (National Initiative for Developing and Harnessing Innovations) scheme is an umbrella program by India’s Department of Science & Technology (DST) to foster innovation and startups. NIDHI i-TBI is a specific component under this umbrella.

• Option (a): Incorrect: While NIDHI has components for prototyping (like PRAYAS), the i-TBI program focuses on supporting the incubators themselves, not directly funding individual students’ prototypes as its primary goal. Incubators then support startups.
• Option (b): Correct: The ‘i’ in i-TBI stands for ‘inclusive’. This component specifically aims to establish and strengthen Technology Business Incubators (TBIs) that cater to innovators and startups working on solutions relevant to social needs, underserved communities, or specific challenges in tier-II/tier-III cities and remote regions, promoting inclusive innovation.
• Option (c): Incorrect: Funding fundamental research in academic institutions is typically handled by other DST schemes or bodies like the Science and Engineering Research Board (SERB), not the NIDHI i-TBI program which focuses on incubation and entrepreneurship.
• Option (d): Incorrect: NIDHI i-TBI focuses on the incubation stage (early-stage support for startups). Creating large-scale manufacturing hubs involves different government initiatives and infrastructure development programs.

Solution: C

While coloured rain (red, yellow, black) often has natural explanations (dust, pollen), reports of distinctly “purple” rain are rare and often linked to specific localized pollutants.

• Option (a): Incorrect: Light scattering by ice crystals produces phenomena like halos, sundogs, or sometimes iridescent clouds, but does not typically result in uniformly purple-coloured raindrops falling over an area.
• Option (b): Incorrect. While pollen or algae can cause yellow, green, or reddish rain (“blood rain”), a distinct purple colour is not typically associated with common biological materials in precipitation.
• Option (c): Correct. Several documented instances of purple rain, for example, in areas with ferromanganese industries or specific types of mining/smelting, have been chemically linked to the presence of manganese (specifically potassium permanganate or related oxidized manganese species) in the rainwater. These compounds can impart a distinct purple colour. Atmospheric scrubbing of industrial plumes containing manganese particulate matter is a likely mechanism.
• Option (d): Incorrect. While atmospheric chemistry involving ozone and NOx is complex and contributes to smog and acid rain, it’s not known to produce purple-coloured precipitation directly. The colours associated with NOx are typically brownish (NO2).

Solution: C

Wolbachia are naturally occurring intracellular bacteria that infect many insect species. Introducing specific strains of Wolbachia into Aedes aegypti mosquito populations (the primary vector for Dengue, Zika, Chikungunya) is an innovative vector control strategy.

• Option (a): Incorrect: While some Wolbachia strains can induce cytoplasmic incompatibility (CI), where infected males mating with uninfected females produce non-viable eggs (used in sterile insect techniques for some species), the primary mechanism used in Dengue control programs like the World Mosquito Program relies on Wolbachia establishing itself in the population and blocking virus transmission. Releasing both infected males and females is often done to establish the infection.
• Option (b): Incorrect: Wolbachia lives inside the mosquito’s cells and does not function as an external larvicide applied to breeding sites. Larvicides are typically chemical or biological agents applied to water.
• Option (c): Correct: This is the key mechanism. When Aedes mosquitoes carry certain strains of Wolbachia, the bacteria compete for resources within the mosquito’s cells or trigger immune responses that make it significantly harder for the Dengue virus (and other viruses like Zika, Chikungunya) to replicate inside the mosquito. This reduces the mosquito’s ability to become infectious and transmit the virus to humans when it bites.
• Option (d): Incorrect: Wolbachia infection does not make the mosquito produce a repellent or stop it from biting humans. It works by reducing the mosquito’s vectorial capacity (its ability to transmit the pathogen).

Solution: D

• PPP plus PPP has been introduced by the Union Minister for Science and Technology on World Diabetes Day
• It is aimed at addressing India’s diabetes epidemic through collaborative efforts between domestic and international stakeholders
• It is a dual layered collaboration model combining Public-private partnership within India and international PPP collaboration
• It seeks to enhance healthcare infrastructure, promote Innovation and make diabetes care accessible and affordable.
• It aims to strengthen India’s health care system by United public and private sectors to develop cost effective and scalable solutions
• It also aims to develop affordable non-invasive devices, increase awareness, ensure treatment and close healthcare-accessibility gaps.

Hence option D is correct

Solution: B

• The First in the World Challenge has been launched by Indian Council of Medical Research.
• The initiative aims to encourage bold unique research that brings first of its kind innovations in the Global Health sector
• It focuses on ‘out of the box’ ideas leading to breakthrough Technologies such as novel vaccines, drugs, diagnostics and interventions.
• The funding criteria includes proposals that should be ground breaking, excluding incremental advancements or process improvements; high risk high reward proposals with Global impact potential are prioritised.
• The selection process will be done by a committee of top experts, innovators and policy makers who will evaluate and select proposals based on originality and potential for impact.

Hence option B is correct

Solution: C

Nanobubbles are ultra tiny bubbles, less than 200 manometers in diameter. They are neutrally buoyant and remains suspended in water for months, enabling efficient gas transfer and surface reactions.

These can be used in:

• Treatment of water – these bubbles remove contaminants, pollutants and pathogens from water and provide for chemical free water purification.
• Oxygen Nanobubbles can enhance health and growth of fish and other aquatic organisms
• These tiny bubbles can penetrate and clean hard to reach areas and are extremely used for industrial cleaning applications
• They can be used in targeted drug delivery and medical imaging;
• These can be used in agriculture – by infusing water with oxygen rich Nanobubbles that significantly help in plant growth

Hence options 1, 2 and 3 are correct

Solution: B

• The Jeddah Commitments were issued at the 4th Global High Level Ministerial Conference on Anti Microbial Resistance hosted by Saudi Arabia at the Red Sea port City of Jeddah in November 2024.
• The World Health Assembly is the Supreme decision-making body of the World Health Organisation where delegations from all WHO member states gather annually to determine policies.

Hence statement 1 is incorrect

• The Jeddah commitments are the collective declaration to open a new chapter in global efforts to address AMR building the coalition of the willing into a powerful force for impact to turn the tide of AMR.
• The Commitments reiterated priority actions from the 79^th United Nations General Assembly high level meeting political declaration on AMR including requesting the Quadripartite to include actions to achieve the 2030 AMR goals of the UNGA political declaration for AMR in the next Global Action Plan.
• The Quadripartite includes the Food and Agriculture Organisation, UNEP, WHO and World Organisation for Animal Health.

Hence statement 2 is correct

• The Jeddah commitments recognised the standards of the Codex Alimentarius Commission and their implementation related to proper use of anti-microbials; Global Anti-Microbial Resistance and Use Surveillance System (GLASS) of World Health Organisation and other critical programs driving Global AMR progress.

Hence statement 3 is correct

Solution: A

• Neuromorphic computing is a technology that is inspired from functions of the human brain and is heavily dependent on biology and neuroscience.
• Neurons are the fundamental units of brain and nervous system
• When a neuron becomes active or spikes, it triggers release of chemical and electrical signals that travel via a network of connection points called Synapses, allowing neurons to connect with each other
• These mechanisms are modelled in neuromorphic computing system through Spiking Neural Network
• A Spiking Neural network is a type of artificial neural network that is composed of Spiking neurons and Synapses.
• Spiking neurons store and process data similar to biological neurones with each neuron having its own charge, delay and threshold values.

Hence statements 1 and 2 are correct and statement 2 correctly explains statement 1

Solution: A

• Global Health Emergency Corps was founded by the WHO in 2023 to address shortcomings and issues uncovered during the Covid 19 response.
• It signifies a unified worldwide initiative to optimise emergency assistance and guarantee prompt actions during health emergencies.

Hence statement 1 is correct

• The Global Antibiotic Research and Development Partnership is a Swiss non profit pharmaceutical research and development organisation that aims to assess antibiotic drug development to counter the threat of antibiotic resistance.
• It was founded by the WHO and the Drugs for Neglected Diseases initiative in 2016 to deliver on the Global Action plan on AMR and became a Swiss foundation in 2018.
• GARDP along with the World Health Organisation recently released a report titled ‘Policy and Regulatory Interventions to Address Antibiotic Shortages in Low- and Middle-Income Countries’; the report analyses Global, National and regional measures to address shortages of antibiotic with a focus on low- and middle-income countries.

Hence statement 2 is incorrect

Solution: A

• India’s gaming industry has seen remarkable growth particularly in digital and online gaming which has become one of the fastest growing sectors in India’s media and entertainment landscape.
• The Bharat Tech Triumph Program has been launched as part of the Create India Challenge season 1 organised by the Interactive Entertainment and Innovation Council in partnership with the Ministry of Information and Broadcasting.
• The program aims to identify and showcase gaming talents of India on the international stage
• The initiative will culminate at the World Audio Visual Entertainment Summit (WAVES) and the India Pavilion at the Game Developer Conference in 2025, providing a global platform for Indian innovators to shine.

Hence option A is correct

Solution: C

• Fluorescent Nano diamonds are nanometer sized diamonds composed of carbon nanoparticle
• They are stable under light, are non toxic and capable of maintaining fluorescence for long periods
• They do not exhibit blinking effect unlike many other Nano scale fluorescent materials
• These are created under high temperature and high pressure conditions
• They are used in biological imaging to track cells over time due to their stability.
• Their ability to detect acceleration and electric fields make them valuable in strategic industries
• FNDs doped with nitrogen vacuum centres can help in exploring Quantum superposition and other quantum mechanical properties.

Hence statements 1 and 2 are correct

Solution: C

• Project Strawberry is the code name of an advanced artificial intelligence model released by OpenAI.
• It is aimed at creating artificial General intelligence that is artificial intelligence with cognitive abilities similar to the human brain.
• The model has shown capability in solving complex puzzles and performing advanced cognitive tasks.
• It is expected to have the capability to perform autonomous research online.

Hence option C is correct

Solution: D

• Notifiable diseases are ones that are legally required to be reported to the government authorities for effective monitoring and response
• The state government is responsible for declaring notifiable disease under public health legislation
• The centre can also recommend diseases for notification.
• Common diseases include Cholera, Tuberculosis, Dengue, AIDS, Chikungunya, Malaria, Dysentery, Diphtheria, Hepatitis, HIV, Influenza, Measles, Rabies, Ebola, Yellow fever, Tetanus, Mumps, Plague.
• Such declaration results in improved surveillance tracking and diagnosis of the disease, prevention of large-scale epidemics, better allocation of healthcare resources and other benefits.

Hence option D is correct

Solution: B

Lokayukta:

• The concept of Lokayukta is derived from the Scandinavian Ombudsman system, designed to investigate complaints against public functionaries.
• The idea was first recommended by the First Administrative Reforms Commission (1966–1970), not the Second ARC.
  (Hence, statement 1 is incorrect)
• The Lokpal and Lokayuktas Act, 2013, passed by Parliament, made it mandatory for every state to establish a Lokayukta within one year from the commencement of the Act (as per Section 63).
• However, it left the framework and structure of the Lokayukta to be decided by the individual states.
  (Hence, statement 2 is correct)
• Maharashtra was the first state to establish a Lokayukta in 1971, well before the enactment of the 2013 legislation.
  (Hence, statement 3 is correct)
• The Lokayukta is usually a retired High Court or Supreme Court judge, appointed by the Governor in consultation with the Chief Justice of the High Court and the Leader of Opposition in the State Assembly.
• The Lokayukta can investigate allegations of corruption and maladministration against public functionaries, including ministers and government officials.
• It has suo motu powers, though its recommendations are not legally binding.

https://timesofindia.indiatimes.com/city/bengaluru/karnataka-special-court-orders-lokayukta-probe-against-cm-siddaramaiah-wife-in-land-case/articleshow/113678255.cms

Solution: A

Poshan Tracker Initiative:

• The Poshan Tracker is a centrally developed ICT-based real-time monitoring system under Mission Poshan 2.0, launched by the Ministry of Women and Child Development (MoWCD).
• It monitors the growth and nutritional status of children aged 0–6 years, using WHO growth charts and Growth Monitoring Devices (GMDs) installed at Anganwadi Centres (AWCs).
• This real-time growth tracking helps detect deviations from normal growth and enables timely nutritional interventions.
  (Hence, statement 1 is correct)
• The application provides a 360-degree view of Anganwadi Centre operations and digitizes the service delivery by Anganwadi Workers (AWWs).
• It replaces traditional paper-based registers and improves the tracking and management of pregnant women, lactating mothers, and children under six.
• Smartphones for AWWs are procured through the Government e-Marketplace (GeM) platform.
  (Hence, statement 2 is correct)
• The nodal ministry is MoWCD, not the Ministry of Health and Family Welfare, and the program is not part of the National Health Mission.
  (Hence, statement 3 is incorrect)
• The initiative also facilitates access to services for migrant beneficiaries, allowing them to avail schemes from the nearest Anganwadi Centre, regardless of original place of registration.

https://pib.gov.in/PressReleaseIframePage.aspx?PRID=2051650

Solution: C

Pradhan Mantri Janjatiya Unnat Gram Abhiyan:

• The Pradhan Mantri Janjatiya Unnat Gram Abhiyan (PM-JUGA) is a centrally supported initiative aimed at holistic development of tribal-majority villages, with a focus on infrastructure, education, health, connectivity, and livelihood.
• The scheme targets around 63,000 villages and seeks to reach approximately 5 crore tribal individuals.
• It operates through the convergence of multiple government schemes, ensuring saturation-level coverage of basic services.
  (Hence, Statement-I is correct)
• Contrary to Statement-II, the scheme explicitly includes tourism-based components such as tribal homestays, aimed at promoting eco-tourism and income generation in tribal areas.
• It also provides targeted support for beneficiaries of the Forest Rights Act (FRA), including livelihood assistance and land development for those holding individual or community forest rights.
  (Hence, Statement-II is incorrect)
• The scheme builds upon the earlier PM Janjati Adivasi Nyaya Maha Abhiyan (JANMAN 2023) and adopts a federal, cooperative approach with the involvement of central and state governments.

https://pib.gov.in/PressReleasePage.aspx?PRID=2055996#:~:text=The%20will%20cover%20around%2063%2C000,villages%20across%2030%20States%20%2F%20UTs

Solution: B

BHASKAR Platform:

• BHASKAR (Bharat Startup Knowledge Access Registry) is a digital platform launched under the Startup India initiative by the Department for Promotion of Industry and Internal Trade (DPIIT).
• It is designed to strengthen India’s startup ecosystem by offering centralized access to knowledge resources and enabling collaboration among startups, investors, mentors, service providers, and government bodies.
  (Hence, statement 1 is correct)
• BHASKAR is not implemented by NITI Aayog. It is an initiative of DPIIT, which operates under the Ministry of Commerce and Industry.
  (Hence, statement 2 is incorrect)
• The platform aims to position India as a global hub for innovation and entrepreneurship, by promoting cross-border collaborations, boosting discoverability of opportunities, and supporting economic growth and job creation.
  (Hence, statement 3 is correct)
• Features include personalized stakeholder IDs, enhanced networking opportunities, and access to startup-related services and schemes.

https://pib.gov.in/PressReleasePage.aspx?PRID=2055243

Solution: C

Project NAMAN:

• Project NAMAN is an initiative launched by the Indian Army to strengthen welfare support for Defence Pensioners, Veterans, and their families.
• The project is closely linked with the SPARSH (System for Pension Administration – Raksha) platform, which is the Ministry of Defence’s digital pension disbursement system.
• Under Project NAMAN, Common Service Centres (CSCs) across India serve as touchpoints for delivering SPARSH-enabled pension services, grievance redressal, and banking assistance.
  (Hence, option (c) is correct)
• These CSCs are managed by veterans or their families and supported by HDFC Bank, promoting employment, community engagement, and empowerment.
• The centres also offer e-Governance services and facilitate financial inclusion by combining digital pension delivery with banking solutions.
• The project reflects the Indian Army’s emphasis on digitisation, accessibility, and honouring ex-servicemen and their families.

Correct Option: B

Justification:

Option (b) The passage states that Mithila paintings originated in the Mithila region of Bihar, traditionally practiced by women in rural households. It also mentions that this art form now enchants art enthusiasts worldwide, showing its global reach.

Other options are incorrect because Mithila paintings often depict a wide range of subjects beyond religious motifs, they have a long history dating back centuries, and they are known for their vibrant colours and intricate designs, contradicting the notion of minimalist use of colours and forms.

Correct Option: D

Justification:

Sol. Let the numbers be a, b, and c respectively.

∴ (?+?)/2−(?+?)/2=24

⇒ (a +c) – (b + c) = 24 × 2 = 48

⇒ a –b = 48

Correct Option: D

Justification:

Let present age of A be x years and that of B be y years

ATQ,

?+1?−5=1/1

⇒ x – y = –6 …(i)

And,

x + y = 54 …(ii)

From (i) and (ii)

x = 24 years and y = 30 years

Required ratio = 30/24=5∶4

Correct Option: C

Justification:

From statement I and II:

P + Q + R + S + T = 5 * 45 = 225 years ———-(1)

P + Q = 106 years ————–(2)

S + T = 94 years —————(3)

From (1), (2) and (3), we get

We get the age of  R .

Correct Option: D

Justification:

Total age of 10 students = 10*20=200 years

Total age of 15 students = 21*15=315years

Total age of 5 new students = 315 – 200= 115 years

• Average age of 5 new students = 115/5 = 23 years