UPSC CSAT Simplified | Up for the challenge? Master these CSAT questions — Practice Set 2 for Prelims 2025

UPSC CSAT Practice Set 2

—Mudit Gupta

QUESTION #1

Read the following passage and answer the item that follows. Your answer should be based on the passage only.

The increasing reliance on artificial intelligence (AI) in decision-making processes has raised significant ethical concerns. While AI systems can process vast amounts of data and identify patterns with remarkable efficiency, they often lack transparency in how decisions are made. This “black box” nature of AI can lead to biased outcomes, particularly when the training data reflects existing societal prejudices. Moreover, the concentration of AI development in the hands of a few large corporations has sparked fears of monopolistic control over critical technologies. In sectors like healthcare and criminal justice, where AI-driven decisions can have life-altering consequences, the need for accountability and fairness is paramount.

Based on the above passage, the following assumptions have been made:

1. The lack of transparency in AI systems can perpetuate societal biases.

2. Decentralizing AI development is essential to ensure fairness and accountability in its applications.

Which of the assumptions given above is/are valid?

A. 1 only

B. 2 only

C. Both 1 and 2

D. Neither 1 nor 2

Explanation:

The passage mentions the “Black Box” nature of the AI models that can accentuate social biases. It means that the training of the AI models can be done using biased data, and hence there is a lack of transparency in the AI systems. So, the first assumption is correct.

The second assumption is partially correct but not fully correct. The passage does mention the monopolistic tendencies of the corporations developing AI systems. However, no assumption has been made that decentralisation is the only solution to this problem. Better regulation of the big corporations by the state can also be one of the solutions, and hence, we cannot assume that the only solution to this problem is decentralisation. Also, to ensure fairness and transparency, better training using more unbiased data can be done to ensure the same. Hence, the second assumption is incorrect.

Therefore, A is the correct answer. 

QUESTION #2 

Let x be a prime number such that 3 < x < 50, then consider the following statements about x^2 – 1:

1. It is always divisible by 8, 12, and 24

2. It will always be a prime number

3. It will always be an odd number

How many statements given above is/are correct?

A. Only 1 statement

B. Only 2 statements 

C. All 3 statements 

D. None of the given statements is correct

Explanation:

In such types of questions, it is always better to assume different values of x, as per the given conditions, and then try and test the statements given above.

As per the given conditions, x can take values like – 5, 7, 11, 13, 17, 19, 23 and so on.

If we assume x = 5, then the value of x^2 will be 24. Now we know that 24 is neither odd nor prime. Hence, the second and the third statements given above are violated. It is always advisable to use the values, as we have used in this example, to test the validity of the given statement.

In the case of the first statement, 24 is divisible by all three numbers i.e. 8, 12, and 24.

To test the validity of the first statement let us take one more value of x = 17. Putting x=17, becomes x^2 -1 becomes 288. 288 is divisible by 8, 12, and 24. Hence, the first statement is correct.

Therefore, A is the correct answer.  (The first statement given above is correct while the second and the third statements are incorrect.)

QUESTION #3

The increase in the price of a certain item was 25%. Then the price decreased by 20% and then again increased by 10%. What is the resultant increase in the price? 

A. 5%

B. 10%

C. 12.5%

D. 15%

Explanation:

Let us assume the initial price of the item is Rs. 100.

When the price is increased by 25%, the new price becomes – 100+ 25% of 100 = Rs. 125

Now, when the price is reduced by 20%, the equation becomes  – 125- 20% of 125= Rs. 100

Now, the price has again increased by 10%. So, the new price becomes – 100+ 10% of 100= Rs. 110

We are asked to find out the percentage change in the overall price.

From the above calculation, it is clear that the initial price was Rs. 100 and the final price is Rs. 110 hence, the percentage change is:

[(110-100)/100]*100% = 10%

Therefore,  B (10%) is the correct answer. 

QUESTION #4

Pointing to a woman in a photograph, Arjun said, “Her husband’s only son is the brother of my sister-in-law.” How is Arjun related to the woman in the photograph?

A. Son

B. Son-in-law

C. Brother

D. Nephew

Explanation:

There is a woman (Let us say Ms. A) in the photograph who has a husband (Let us say Mr. B). This couple has one son only (Ler us say the name of the son is Mr. X). The son (Mr. X) has a sister (Let us say, Ms. Y), who is the sister-in-law of Arjun. It means that Arjun is married to the sister of Y. If Arjun is married to the sister of Y, then he is the son-in-law of Ms. A and Mr. B.

Therefore, B (Son-in-law) is the correct answer. 

QUESTION #5

In a queue, Mr A is 12th from the front and Mr B is 15th from the end, while Mr C is exactly in between Mr A and Mr B. If Mr A is ahead of Mr B and there are 50 persons in the queue, how many persons are there between Mr A and Mr C?

A. 9

B. 10

C. 11

D. 12

Explanation:

While solving such questions of rank test, one equation should always be kept in mind:

Rank from front = Total – Rank from back

Using the above equation we can arrive at the following:

Rank of A from front = 12

Rank of B from front = 36

Since, C is exactly in the middle of A and B, so:

Rank of C = (Rank of A + Rank of B) / 2

Rank of C =  (12 + 36) / 2

Since the rank of A is 12 and the Rank of C is 24, we can easily tell that 11 people are standing between A and C.

Therefore, C (11) is the correct answer.

(About our Expert: Mudit Gupta has been a mentor and faculty for the UPSC Civil Services exam for 8 years with expertise in CSAT, Polity, International Relations, and Current Affairs. He is known to break complex concepts into simpler ones that allow UPSC aspirants to develop a grip over the subject matter.)

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