UPSC Prelims 2021 · CSAT (Paper II): On the basis of the passage given above, the following assumptions have been made…

UPSC Prelims 2021 · CSAT (Paper II)
Read the passage

A social and physical environment riddled with poverty, inequities, unhygienic and insanitary conditions generates the risk of infectious diseases. Hygiene has different levels : personal, domestic and community hygiene. There is no doubt that personal cleanliness brings down the rate of infectious diseases. But the entry of the market into this domain has created a false sense of security that gets conditioned and reinforced by the onslaught of advertisements. Experience in Western Europe shows that along with personal hygiene, general improvements in environmental conditions and components like clean water, sanitation and food security have brought down infant/child death/infection rates considerably. The obsession with hand hygiene also brings in the persisting influence of the market on personal health, overriding or marginalising the negative impact on ecology and the emergence of resistant germs.

On the basis of the passage given above, the following assumptions have been made :

  • 1. People who are obsessed with personal hygiene tend to ignore the community hygiene.
  • 2. Emergence of multi-drug resistant germs can be prevented by personal cleanliness.
  • 3. Entry of the market in the domain of hygiene increases the risk of infectious diseases.
  • 4. Scientific and micro-level interventions are not sufficient to bring down the burden of infectious diseases.
  • 5. It is community hygiene implemented through public health measures that is really effective in the battle against infectious diseases.

Which of the above assumptions are valid ?

Answer (c) & explanation

Assumptions 4 and 5 are valid (c). Step 1: the passage says Western Europe cut infections through clean water, sanitation, food security and hygiene for all. So small-scale, personal steps are not enough (4), and community hygiene through public health works (5). Step 2: assumption 3 says the market raises the risk. The passage says the market creates a false sense of security, not higher risk. Step 3: assumption 2 says personal cleanliness can prevent drug-resistant germs; not supported. Assumption 1 is also not stated. So options (a), (b) and (d) fail.

Tip: "false sense of security" is not the same as "increased risk". Check the exact claim, not just the topic.

Answer as per the official UPSC answer key.

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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