UPSC Prelims 2025 · CSAT (Paper II): Which one of the following statements best reflects the most logical, rational and crucial…

UPSC Prelims 2025 · CSAT (Paper II)
Read the passage

A single number for inflation is aggregate across different commodities and Services the price rise differs for different items of consumption. So, the single number is arrived at by assigning weights to different commodities and services. For WPI, the weights in production are used; for CPI, the consumption basket is used. But people are not homogeneous.
The consumption basket is vastly different for the poor, the middle classes, and the rich. Hence, the CPI is different for each of these classes and a composite index requires averaging the baskets.

Which one of the following statements best reflects the most logical, rational and crucial message conveyed by the passage?

Answer (b) & explanation

The message is that the present single inflation number does not correctly show the price rise of individual items (b). Step 1: the passage says one inflation number is an average of many items, each given a weight. Prices of different items rise differently. Step 2: it adds that consumption baskets differ for the poor, middle class and rich, so one composite CPI averages them too. So the single number hides how individual prices move: (b). Step 3: option (a), scrap CPI and use only WPI, and (d), inflation data is useless, are extreme. Option (c), services under-represented, is not discussed.

Tip: WPI uses production weights; CPI uses consumption weights. Since 2014 the RBI targets CPI inflation at 4% (with a band of 2–6%).

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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