UPSC CISF-AC-EXE Archives

31. In a game between X and Y, X has to give ₹ 10 each time he loses to Y.

In a game between X and Y, X has to give ₹ 10 each time he loses to Y. If he wins, then he gets ₹ 50 from Y. If they play 15 times and X earns ₹ 450, how many times does X win ?

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Let W be the number of times X wins and L be the number of times X loses. The total number of games played is W + L = 15. When X wins, he gains ₹ 50, so the total gain from wins is 50W. When X loses, he gives ₹ 10, so the total loss from losses is 10L. X’s net earning is the total gain minus the total loss, which is 50W – 10L. We are given that X earns ₹ 450, so 50W – 10L = 450. We now have a system of two linear equations: 1) W + L = 15 and 2) 50W – 10L = 450. From equation 1, L = 15 – W. Substituting this into equation 2: 50W – 10(15 – W) = 450. 50W – 150 + 10W = 450. 60W – 150 = 450. 60W = 600. W = 600 / 60 = 10. X wins 10 times.

– Define variables for the number of wins and losses.
– Set up one equation based on the total number of games played.
– Set up a second equation based on the total net earning (total gain from wins minus total loss from losses).
– Solve the system of linear equations for the number of wins.

This is an algebra word problem that requires setting up and solving a system of equations. It’s important to correctly represent the gain and loss per game and relate the total gain/loss to the net earning. Checking the answer (10 wins, 5 losses: 10*50 – 5*10 = 500 – 50 = 450) confirms the solution.

32. Who among the following is the author of the book ‘Rajtarangini’ ?

Who among the following is the author of the book ‘Rajtarangini’ ?

Bilhana

Kalhana

Banabhatta

Bhavabhuti

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‘Rajtarangini’ (meaning “River of Kings”) is a historical chronicle of early Kashmir written in Sanskrit by Kalhana in the 12th century CE. It is considered one of the earliest and most important works of history from India.

– Kalhana was a Kashmiri Brahman poet, historian, and philosopher.
– ‘Rajtarangini’ is a comprehensive history of the kings of Kashmir up to Kalhana’s time, drawing upon various sources.
– The other options are authors known for different works in Sanskrit literature: Bilhana (Vikramankadevacharitam), Banabhatta (Harshacharita, Kadambari), and Bhavabhuti (Mahaviracharitam, Uttararamacharitam).

‘Rajtarangini’ stands out among classical Indian texts for its attempt at presenting a chronological history, although it mixes historical accounts with myths and legends. It remains a valuable source for the history of Kashmir and north-western India.

33. Who among the following directed the film ‘Subarnarekha’ made on the p

Who among the following directed the film ‘Subarnarekha’ made on the partition of India ?

Satyajit Ray

Mrinal Sen

Bimal Roy

Ritwik Ghatak

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The film ‘Subarnarekha’ (1965) is a critically acclaimed Bengali film directed by Ritwik Ghatak. It is the third film in his trilogy dealing with the trauma of the Partition of India, following ‘Meghe Dhaka Tara’ (1960) and ‘Komal Gandhar’ (1961).

– Ritwik Ghatak was a prominent Indian filmmaker and scriptwriter, known for his socially relevant films often dealing with themes of Partition and displacement.
– ‘Subarnarekha’ is considered one of his masterpieces and a significant work in Indian cinema.
– The other directors listed (Satyajit Ray, Mrinal Sen, Bimal Roy) are also renowned figures in Indian cinema but are not the directors of ‘Subarnarekha’. Satyajit Ray directed the Apu Trilogy (‘Pather Panchali’, ‘Aparajito’, ‘Apur Sansar’), Mrinal Sen directed films like ‘Bhuvan Shome’ and ‘Akaler Sandhane’, and Bimal Roy directed films like ‘Do Bigha Zamin’ and ‘Devdas’.

The Partition of India had a profound impact on the social and cultural landscape, and it has been a recurring theme in Indian literature and cinema, explored by various artists including Ritwik Ghatak, who himself was a refugee.

34. Which one of the following pairs correctly represents an example of an

Which one of the following pairs correctly represents an example of analogous organs ?

Forelimb of horse and human arm

Human hands and wings of birds

Wings of birds and wings of insects

Flipper of whale and forelimb of frog

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Analogous organs are organs that perform similar functions but have different evolutionary origins and structures. Wings of birds and wings of insects both serve the function of flight, but their underlying structures are fundamentally different. Bird wings are modified forelimbs with bones covered by feathers, while insect wings are chitinous extensions of the body wall, supported by veins. This difference in structure despite similar function makes them analogous organs.

– Analogous organs arise from convergent evolution, where unrelated organisms evolve similar traits due to similar environmental pressures.
– They have similar functions but different basic structures and origins.
– Homologous organs, in contrast, have similar structures and origins (due to common ancestry) but may have different functions.

Examples of homologous organs include the forelimbs of vertebrates (human arm, whale flipper, bat wing, horse leg), which share a common bone structure despite different functions. Examples of analogous organs include the eye of a squid and the eye of a vertebrate, or the spines of a cactus and the spines of a euphorbia.

35. Which one of the following groups of organisms correctly makes a food

Which one of the following groups of organisms correctly makes a food chain ?

Grass, Goat, Human

Elephant, Goat, Grass

Tiger, Snake, Grass

Insect, Frog, Grass

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A food chain illustrates the flow of energy in an ecosystem, starting with a producer. In Option A, Grass is a producer (plants), Goat is a primary consumer that eats grass, and Human is a secondary or tertiary consumer that can eat goat. This correctly shows a linear flow of energy from producer to consumers. The other options present incorrect or reversed sequences that do not represent a valid food chain: B) Elephant and Goat both eat Grass, but there’s no flow shown between Elephant/Goat and Grass in the order presented. C) Tiger eats animals, Snake eats animals, Grass is a producer – no correct flow. D) Insect eats Grass, Frog eats Insect, Grass is a producer – the order is incorrect.

– A food chain starts with a producer (organism that makes its own food, usually plants).
– The arrows in a food chain indicate the direction of energy flow (from the organism being eaten to the organism that eats it).
– The sequence is typically Producer -> Primary Consumer (Herbivore) -> Secondary Consumer (Carnivore/Omnivore) -> Tertiary Consumer, etc.

Food chains are simplified models of energy flow in ecosystems. In reality, organisms often have multiple food sources, forming complex food webs. Understanding food chains helps to understand ecological relationships and energy transfer efficiency.

36. Which one among the following is the most reactive metal?

Which one among the following is the most reactive metal?

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The reactivity of alkali metals increases down the group (K > Na) and alkali earth metals are generally less reactive than alkali metals. Comparing the given options, the standard reactivity series shows Potassium (K) is more reactive than Sodium (Na), which is more reactive than Calcium (Ca), which is more reactive than Magnesium (Mg). Therefore, Potassium (K) is the most reactive metal among the given choices.

– Reactivity of metals is related to their tendency to lose electrons (become oxidized).
– Alkali metals (Group 1) are generally more reactive than alkaline earth metals (Group 2).
– Within alkali metals, reactivity increases down the group.
– Within alkaline earth metals, reactivity generally increases down the group (though sometimes variations occur, but the general trend holds for Ca vs Mg).
– The order of reactivity for the given options is approximately K > Na > Ca > Mg.

Reactivity series can be determined experimentally (e.g., reaction with water, air, acids) or understood based on electronic configuration and ionization energies. Metals higher in the reactivity series can displace metals lower in the series from their compounds.

37. A man takes a loan at 5% simple interest for a period of 2 years. He i

A man takes a loan at 5% simple interest for a period of 2 years. He immediately gives this money on loan at 5% compound interest for 2 years. What is the amount of loan he has taken if he makes a profit of ₹ 2,100 ?

₹ 8,00,000

₹ 4,20,000

₹ 1,00,000

₹ 8,40,000

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Let the principal amount be P. The simple interest (SI) paid by the man for 2 years at 5% is SI = (P * 5 * 2) / 100 = 0.10P. The compound interest (CI) received by the man for 2 years at 5% is CI = P(1 + 5/100)^2 – P = P(1.05)^2 – P = P(1.1025) – P = 0.1025P. The man’s profit is the difference between the CI received and the SI paid: Profit = CI – SI = 0.1025P – 0.10P = 0.0025P. Given the profit is ₹ 2,100, we have 0.0025P = 2100. Solving for P: P = 2100 / 0.0025 = 2100 / (1/400) = 2100 * 400 = ₹ 8,40,000.

– Simple Interest formula: SI = PRT/100.
– Compound Interest formula: CI = Amount – Principal = P(1 + R/100)^T – P.
– The profit in this scenario is the difference between the interest earned (CI) and the interest paid (SI).
– Set up an equation with the profit difference equal to the given profit amount and solve for the principal P.

This question tests the understanding of simple and compound interest calculations and how to find the profit earned by an intermediary who borrows at one rate/type and lends at another rate/type. The difference in interest earned versus interest paid constitutes the profit.

38. A businessman lost 20% of his goods due to rain. The remaining items w

A businessman lost 20% of his goods due to rain. The remaining items were sold at a profit of 50%. The businessman earned an overall profit of:

10%

30%

20%

40%

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Assume the total cost price of the goods was ₹ 100. Let the total quantity be 100 units, so the cost per unit is ₹ 1. 20% of goods were lost, meaning 20 units were lost. Remaining goods are 100 – 20 = 80 units. These 80 units are sold at a profit of 50% on their cost. The cost of the 80 units is ₹ 80 (since cost per unit was ₹ 1). Selling price of these 80 units = Cost * (1 + Profit%) = ₹ 80 * (1 + 0.50) = ₹ 80 * 1.50 = ₹ 120. The businessman invested ₹ 100 initially (the cost of the total goods) and received ₹ 120 from the sale. The overall profit is ₹ 120 – ₹ 100 = ₹ 20. Overall profit percentage = (Overall Profit / Total Cost) * 100 = (₹ 20 / ₹ 100) * 100 = 20%.

– The profit/loss is calculated on the original total cost of the goods, even if a portion is lost.
– The selling price is calculated based on the goods that *are* sold, applying the given profit margin to their cost.
– Overall profit = Total Revenue – Total Cost.
– Overall profit percentage = (Overall Profit / Total Cost) * 100.

Setting the initial cost price to a convenient value like ₹ 100 simplifies calculations for percentage problems. The loss of goods means the cost invested in those goods is not recovered, and this must be accounted for in the overall profit calculation.

39. ‘A’ and ‘B’ have pocket money in the ratio of 3 : 4. After the day’s w

‘A’ and ‘B’ have pocket money in the ratio of 3 : 4. After the day’s work, ‘A’ earned ₹ 600 while ‘B’ earned ₹ 500. However, ‘A’ spent ₹ 150 and ‘B’ spent ₹ 100 during the day. If they have equal amount of money at the end of the day, then the pocket money ‘A’ had in the morning is:

₹ 150

₹ 200

₹ 250

₹ 100

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Let A’s initial pocket money be 3x and B’s initial pocket money be 4x. At the end of the day, A’s total money is 3x + ₹ 600 – ₹ 150 = 3x + ₹ 450. B’s total money is 4x + ₹ 500 – ₹ 100 = 4x + ₹ 400. Since they have equal amounts at the end, 3x + 450 = 4x + 400. Solving for x, we get x = 50. A’s initial pocket money was 3x, which is 3 * 50 = ₹ 150.

– Represent the initial amounts using the given ratio with a variable (e.g., 3x and 4x).
– Formulate expressions for the final amounts for A and B by adding earnings and subtracting spending.
– Set the final amounts equal to each other based on the problem statement.
– Solve the resulting linear equation for the variable x.
– Calculate the initial pocket money for A using the value of x.

This is a typical word problem involving ratios and linear equations. Careful tracking of money earned and spent for each person is crucial. The phrase “equal amount of money at the end of the day” provides the equation needed to solve for the unknown variable.

40. Which one of the following Summits/Conferences is not correctly paired

Which one of the following Summits/Conferences is not correctly paired with the place of the summit/conference?

UN 2023 Water Conference : New York

SDG Summit 2023 : Washington, DC

Climate Ambition Summit 2023 : New York

COP 28 : Dubai

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The SDG Summit 2023 was held at the United Nations Headquarters in New York, not Washington, DC. The UN 2023 Water Conference, Climate Ambition Summit 2023, and COP 28 were correctly paired with their respective locations: New York, New York, and Dubai.

– The SDG Summit 2023 took place at the UN Headquarters in New York from September 18-19, 2023, during the High-Level Week of the UN General Assembly.
– The UN 2023 Water Conference was held in New York from March 22-24, 2023.
– The Climate Ambition Summit 2023 was convened by the UN Secretary-General and held in New York on September 20, 2023.
– COP 28 was held in Dubai, United Arab Emirates, from November 30 to December 13, 2023.

These summits and conferences are significant global events addressing critical issues like sustainable development, water management, climate change, and international cooperation. Knowing their locations is important for current affairs awareness.