UPSC Prelims 2023 · CSAT (Paper II): Which one of the following statements best implies the most rational assumption that can…

UPSC Prelims 2023 · CSAT (Paper II)
Read the passage

Environmental problems cause health problems. Substantial changes in lifestyle can reduce environmental or health problems, but this idea appears almost impossible to adopt. With environmental problems, individual efforts can be perceived as having a negligible effect and therefore lead to inertia. With health, on the other hand, individual choices can make the difference between life and death, literally. And yet, barring a few, there seems to be the same collective lethargy towards making their choices.

Which one of the following statements best implies the most rational assumption that can be made from the passage ?

Answer (a) & explanation

The rational assumption is that we are likely to spend more on cure than prevention (a). Step 1: the passage says lifestyle changes could cut health problems. Step 2: but people show "collective lethargy" about making those choices, even when life and death are at stake. If they will not prevent illness, they will later pay for cure. That is (a). Step 3: option (c), health protected while environmental problems go on, goes against the first line. Options (b), government's job, and (d), western values, are not in the passage.

Tip: an assumption often follows from the passage's main complaint. Here the complaint is inaction on prevention.

Answer as per the official UPSC answer key.

Same theme in UPSC Mains

Related questions from other years

UPSC Prelims 2026 · CSAT (Paper II)

Question : X receives three coins of different denominations : 1, 2, 5, 10 and 20. If the total amount received by X is m, does X receive a coin of denomination 5?

Statement I : m is not a prime number.

Statement II : The sum of the digits of m is greater than 5.

Answer (a) & explanation

Statement II alone is enough; Statement I alone is not (a). Step 1: three different coins from 1, 2, 5, 10, 20 give ten totals. With a 5: 8, 16, 17, 26, 27, 35. Without a 5: 13, 23, 31, 32. Step 2: Statement I (m not prime): 8, 16, 26, 27, 35 have a 5, but 32 (2 + 10 + 20) does not. Mixed answers, so I fails. Step 3: Statement II (digit sum above 5): 8, 16, 17, 26, 27, 35 qualify, and every one has a 5. (13, 23, 31, 32 have digit sums 4, 5, 4, 5.) So II answers "yes". Options (b), (c) and (d) fail.

Tip: when cases are few, list them all. Then check each statement against the full list.

Trap

don't assume both statements are needed. Listing all ten cases takes thirty seconds and settles it.

Answer as per the official UPSC answer key.

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UPSC Prelims 2026 · CSAT (Paper II)
Read the passage

How is deflation done? Most countries use a method called ‘double deflation’, where input and output prices are deflated separately. Consider a manufacturer importing oil for use in production. If oil prices fall, output prices do not and quantities remain the same, real value added should not change. But if the same deflator is used for inputs and outputs, as in India, it would look as if the manufacturer had become more productive.

Which of the following assumptions is/are valid?

  • 1. Deflation strategies can be used to make manufacturers appear to be doing better than they actually are.
  • 2. When input and output prices are both deflated against a single input price, it is referred to as ‘double deflation’.

Select the answer using the code given below.

Answer (a) & explanation

Only assumption 1 is valid (a). Step 1: the passage says that using one deflator for inputs and outputs, as in India, makes it "look as if the manufacturer had become more productive". So deflation methods can make firms appear better than they are (1). Step 2: assumption 2 says double deflation means deflating both against a single price. But the passage defines double deflation as deflating inputs and outputs separately. So 2 reverses the definition. Step 3: options (b), (c) and (d) fail.

Tip: check definitions word for word against the passage. Deflating means removing the effect of price changes to find real growth, as in real GDP.

Answer as per the official UPSC answer key.

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UPSC Prelims 2026 · CSAT (Paper II)

P, Q, R, S and T are ranked 1 to 5 (not necessarily in that order). The rank of P is 4, the rank of Q is not 5, the rank of R is 1, the rank of S is not 2, the rank of T is not 3. Then which of the following is/are correct?

  • I. If the rank of S is 3, then that of T is 2.
  • II. If the rank of Q is 3, then that of T is 5.

Select the answer using the code given below.

Answer (d) & explanation

Neither statement is correct (d). Step 1: P = 4 and R = 1 are fixed. Ranks 2, 3 and 5 remain for Q, S and T, with rules: Q is not 5, S is not 2, T is not 3. Step 2: statement I: if S = 3, then Q and T share 2 and 5. Q cannot be 5, so Q = 2 and T = 5, not 2. I is wrong. Step 3: statement II: if Q = 3, then S and T share 2 and 5. S cannot be 2, so S = 5 and T = 2, not 5. II is wrong. Options (a), (b) and (c) fail.

Tip: fix the known ranks first, then apply each "if" condition and let the "not" rules decide the rest. Write the small table on paper.

Answer as per the official UPSC answer key.

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UPSC Prelims 2026 · CSAT (Paper II)

How many times does 5 appear in all two-digit positive integers?

Answer (b) & explanation

The digit 5 appears 19 times (b). Step 1: 5 in the tens place: 50, 51, …, 59 = 10 times. Step 2: 5 in the units place: 15, 25, 35, 45, 55, 65, 75, 85, 95 = 9 times (05 is not a two-digit number). Step 3: total = 10 + 9 = 19. The number 55 has two 5s, and both are counted. Option (a), 18, counts 55 once. Options (c) and (d) wrongly add 05 or 5.

Tip: count place by place. The question asks how many times the digit appears, not how many numbers contain it (that would be 18).

Answer as per the official UPSC answer key.

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