Prelims Solution

Q. A has some coins. He gives half of the coins and 2 more to B. B gives half of the coins and 2 more to C. C gives half of the coins and 2 more to D. The number of coins D has now, is the smallest two- digit number. How many coins does A have in the beginning?

Q. A has some coins. He gives half of the coins and 2 more to B. B gives half of the coins and 2 more to C. C gives half of the coins and 2 more to D. The number of coins D has now, is the smallest two- digit number. How many coins does A have in the beginning?

a. 76
b. 68
c. 60
d. 52
Correct Answer: d. 52

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 

A has some coins

Let’s solve this step by step:

1. Initial Condition:
– A has x coins
– A gives half of coins plus 2 to B

2. After first transfer (A to B):
– A has: x/2 – 2 coins
– B has: x/2 + 2 coins

3. After second transfer (B to C):
– B gives half plus 2 to C
– B has: (x/2 + 2)/2 – 2 = x/4 – 1 coins
– C has: (x/2 + 2)/2 + 2 = x/4 + 3 coins

4. After third transfer (C to D):
– C gives half plus 2 to D
– C has: (x/4 + 3)/2 – 2 = x/8 – 1/2 coins
– D has: (x/4 + 3)/2 + 2 = x/8 + 7/2 coins

5. Given condition:
– D has smallest two-digit number (10)
– Therefore: x/8 + 7/2 = 10

6. Solve for x:
– x/8 + 7/2 = 10
– x/8 = 10 – 7/2
– x/8 = 6.5
– x = 52

Verification:
– A starts with 52 coins
– B gets 28 coins (26 + 2), A keeps 24
– C gets 16 coins (14 + 2), B keeps 12
– D gets 10 coins (8 + 2), C keeps 6

Answer: A had 52 coins initially

Q. A has some coins. He gives half of the coins and 2 more to B. B gives half of the coins and 2 more to C. C gives half of the coins and 2 more to D. The number of coins D has now, is the smallest two- digit number. How many coins does A have in the beginning? Read More »

Q. On one side of a 1.01 km long road, 101 plants are planted at equal distance from each other. What is the total distance between 5 consecutive plants?

Q. On one side of a 1.01 km long road, 101 plants are planted at equal distance from each other. What is the total distance between 5 consecutive plants?

a. 40 m
b. 40.4 m
c. 50 m
d. 50.5 m
Correct Answer: b. 40.4 m

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 

101 plants on a 1.01 km road

Given information:
– Road length: 1.01 km = 1010 meters
– Total plants: 101
– Plants are equally spaced
– First plant at 0 meters
– Last plant at 1010 meters

Solution steps:

1. Find total gaps between plants:
– Total gaps = Total plants – 1
– Total gaps = 101 – 1 = 100 gaps

2. Find distance between consecutive plants:
– Distance = Total length ÷ Number of gaps
– Distance = 1010 ÷ 100 = 10.1 meters

3. Find distance for 5 consecutive plants:
– Number of gaps = Number of plants – 1
– Number of gaps = 5 – 1 = 4 gaps
– Total distance = Distance per gap × Number of gaps
– Total distance = 10.1 × 4 = 40.4 meters

Answer: The distance between 5 consecutive plants is 40.4 meters

On one side of a 1.01 km long road

Q. On one side of a 1.01 km long road, 101 plants are planted at equal distance from each other. What is the total distance between 5 consecutive plants? Read More »

How many 3-digit natural numbers (without repetition of digits) are there such that each digit is odd and the number is divisible by 5?

Q. How many 3-digit natural numbers (without repetition of digits) are there such that each digit is odd and the number is divisible by 5?

a. 8
b. 12
c. 16
d. 24
Correct Answer: b.12

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 

How many 3 digit natural numbers ??

Given conditions:
– Must be a 3-digit number
– All digits must be odd
– No repetition of digits allowed
– Number must be divisible by 5

Solution steps:

1. For divisibility by 5:
– Last digit must be either 0 or 5
– Since only odd digits allowed, last digit must be 5

2. Available odd digits: 1, 3, 5, 7, 9
– 5 is already used in units place
– Remaining digits for other positions: 1, 3, 7, 9

3. Filling other positions:
– Hundreds place: 4 choices (1, 3, 7, 9)
– Tens place: 3 choices (remaining digits after hundreds place)

4. Total possible numbers:
– Using multiplication principle
– 4 × 3 = 12 different numbers

Answer: 12 three-digit numbers possible

How many 3-digit natural numbers (without repetition of digits) are there such that each digit is odd and the number is divisible by 5? Read More »

Question: Is x an integer? Statement-1: x/3 is not an integer. Statement-2: 3x is an integer.

Q. Consider the Question and two Statements given below:

Question: Is x an integer?
Statement-1: x/3 is not an integer.
Statement-2: 3x is an integer.

Which one of the following is correct in respect of the Question and the Statements?
a.    Statement-1 alone is sufficient to answer the Question
b.   Statement-2 alone is sufficient to answer the Question
c.    Both Statement-1 and Statement-2 are sufficient to answer the Question
d.   Both Statement-1 and Statement-2 are not sufficient to answer the Question
Correct Answer: d.   Both Statement-1 and Statement-2 are not sufficient to answer the Question

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 

Is x an integer?

Statement-1: x/3 is not an integer

– This tells us x cannot be evenly divided by 3
– Examples: x could be 2/3 (not an integer) or 4 (integer)
– Statement-1 alone is not sufficient

Statement-2: 3x is an integer

– This means x could be an integer or a fraction multiple of 1/3
– Examples: if 3x = 6, then x = 2 (integer)
if 3x = 2, then x = 2/3 (not integer)
– Statement-2 alone is not sufficient

Combined Analysis:
– Statement-1: x cannot be evenly divided by 3
– Statement-2: 3x is an integer
– Together they tell us x must be a fraction multiple of 1/3
– Still cannot determine if x is definitely an integer

Answer: Both Statement-1 and Statement-2 are not sufficient to answer the Question.

Question: Is x an integer? Statement-1: x/3 is not an integer. Statement-2: 3x is an integer. Read More »

Q. A man completes 7/8 of a job in 21 days. How many more days will it take him to finish the job if quantum of work is further increased by 50%

Q. A man completes 7/8 of a job in 21 days. How many more days will it take him to finish the job if quantum of work is further increased by 50%

(a) 24
(b) 21
(c) 18
(d) 15
Correct Answer: (d) 15

Question from UPSC Prelims 2021 CSAT Paper

Explanation : 

A man completes 7/8 of a job in 21 days ….

Given:
– Man completes 7/8 of work in 21 days
– Work increases by 50%

Step 1: Find Rate of Work
– Total work = W
– Rate = (7/8)W ÷ 21 = W/24 per day

Step 2: Calculate New Work
– Increased work = 1.5W
– Already completed = 7/8W
– Remaining = 1.5W – 7/8W = 5/8W

Step 3: Calculate Days Required
– Time = Remaining work ÷ Rate
– = (5/8W) ÷ (W/24)
– = 15 days

Answer: 15 additional days required

Man completes 7/8 work in 21 days

Q. A man completes 7/8 of a job in 21 days. How many more days will it take him to finish the job if quantum of work is further increased by 50% Read More »

Q. In India, the objective of macroeconomics policy is to enhance the economic welfare of the people, and any one wing of such macro policy, monetary or fiscal, cannot independently work without active support of another.

Q. In India, the objective of macroeconomics policy is to enhance the economic welfare of the people, and any one wing of such macro policy, monetary or fiscal, cannot independently work without active support of another.

Q 1. Which one of the following statements best reflects the corollary to the passage given above?

(a) The central bank cannot work independently of the Government.
(b) Government should regulate financial markets and institutions closely.
(c) Market economy is not compatible with the socialist policies of the Government.
(d) Financial sector reforms are required for enhancing the economic welfare of the people.

Question from UPSC Prelims 2021 CSAT Paper

Explanation : 

Q1: Correct Answer – (a) The central bank cannot work independently of the Government.

Explanation – (a) The central bank cannot work independently of the Government: This option suggests that the central bank and the government must work together in order to achieve their objectives. In the context of the passage, this means that monetary and fiscal policies must be coordinated in order to enhance the economic welfare of the people.

(b) Government should regulate financial markets and institutions closely: This option suggests that it is important for the government to closely monitor and regulate financial markets and institutions. While this may be a valid statement in general, it does not directly follow from the passage.

c) Market economy is not compatible with socialist policies of the Government: This option suggests that there is a conflict between a market economy and socialist policies implemented by the government. While this may be a topic for debate, it does not directly follow from the passage.

(d) Financial sector reforms are required for enhancing economic welfare of people: This option suggests that reforms in the financial sector are necessary in order to improve economic welfare. While this may be true, it does not directly follow from the passage which focuses on coordination between monetary and fiscal policies.

Q. In India, the objective of macroeconomics policy is to enhance the economic welfare of the people, and any one wing of such macro policy, monetary or fiscal, cannot independently work without active support of another. Read More »

Q. The resolution of bankruptcy cases of Indian banks under the Insolvency and Bankruptcy Code should help bring non-performing assets (NPA) situation under some control.

Q. The resolution of bankruptcy cases of Indian banks under the Insolvency and Bankruptcy Code should help bring non-performing assets (NPA) situation under some control.

Despite the slow pace of resolution by the National Company Law Tribunal, the Code can be helpful in cleaning up bank books in future credit cycles. The recapitalization of public sector banks too can help increase the capital cushion of banks and induce them to lend more and boost economic activity. But bad debt resolution and recapitalization are only a part of the solution as they, by themselves, can do very little to rein in reckless lending that has pushed the Indian banking system to its current sorry state. Unless there are systemic reforms that address the problem of unsustainable lending, future credit cycles will continue to stress the banking system.

Q 1. Which one of the following statements best reflects the most logical, rational and practical suggestion implied by the passage given above?
(a) Lending by the banks should be closely monitored and regulated by the central Government.
(b) Interests rates should be kept low so as to induce banks to lend more, promote credit growth and thereby boost economic activity.
(c) Merger of many banks into a few large banks alone in the long-term solution to make them viable and prevent their bad performance.
(d) Indian banking system requires structural reforms as a long-term solution for bad loans problem.

Question from UPSC Prelims 2021 CSAT Paper

Explanation : 

Q1: Correct Answer – (d) Indian banking system requires structural reforms as a long-term solution for bad loans problem.

Explanation – The most logical, rational and practical suggestion implied by the passage given above is that the Indian banking system requires structural reforms as a long-term solution for bad loans problem (option d). The passage suggests that while resolution of bankruptcy cases and recapitalization of public sector banks can help in cleaning up bank books and increasing their capital cushion, they are only a part of the solution. Systemic reforms that address the problem of unsustainable lending are necessary to prevent future credit cycles from stressing the banking system.

Q. The resolution of bankruptcy cases of Indian banks under the Insolvency and Bankruptcy Code should help bring non-performing assets (NPA) situation under some control. Read More »

Q. In the immediate future, we will see the increasing commodification of many new technologies –

Q. In the immediate future, we will see the increasing commodification of many new technologies –

artificial intelligence and robotics, 3D manufacturing, custom made biological and pharmaceutical products, lethal autonomous weapons and driverless cars. This will pose conundrums. The moral question of how a driverless car will decide between hitting jaywalker and swerving and damaging the car has often been debated. The answer is both simple- save the human life- and complex. At which angle should the car swerve- just enough to save the jaywalker or more than enough? If the driverless car is in Dublin, who would take the decision ? The Irish Government, or the car’s original code writer in California, or a software programmer in Hyderabad to whom maintenance is outsourced ? If different national jurisdictions have different fine print on prioritizing a human life, how will it affect insurance and investment decisions, including transnational ones?

Q 1. Which of the following statements best reflect the rational, plausible, and practical implications that can be derived from the passage given above?
1. Too much globalization is not in the best interests of any country.
2. Modern technologies are increasingly blurring the economic borders.
3. Innovation and capital have impinged on the domain of the state.
4. Public policy of every country should focus on developing its own supply chains.
5. Geopolitics will have to reconcile to many ambiguities and uncertainties.
Select the correct answer using the code given below:
(a) 1, 4 and 5 only
(b) 1, 2, 3 and 4 only
(c) 2, 3 and 5 only
(d) 1, 2, 3, 4 and 5

Question from UPSC Prelims 2021 CSAT Paper

Explanation : 

Q1: Correct Answer – (c) 2, 3 and 5 only

Explanation – 1. Too much globalization is not in the best interests of any country: This statement suggests that excessive globalization could have negative consequences for individual countries. However, this idea is not explicitly mentioned or implied in the passage.

2. Modern technologies are increasingly blurring the economic borders: This statement reflects the idea presented in the passage that new technologies such as driverless cars and custom-made biological products can create complex transnational issues that challenge traditional economic boundaries.

3. Innovation and capital have impinged on the domain of the state: This statement reflects the idea presented in the passage that new technologies and their associated capital flows can create complex issues that challenge traditional notions of state sovereignty and control.

4. Public policy of every country should focus on developing its own supply chains: This statement suggests that countries should prioritize developing their own supply chains to mitigate potential negative effects of globalization. However, this idea is not explicitly mentioned or implied in the passage.

5. Geopolitics will have to reconcile to many ambiguities and uncertainties: This statement reflects the idea presented in the passage that new technologies can create complex transnational issues with many ambiguities and uncertainties, which will require adaptation from geopolitical actors.

So based on these explanations, option © 2, 3 and 5 only remains as a correct answer.

Q. In the immediate future, we will see the increasing commodification of many new technologies – Read More »

Q. Nothing can exist in a natural state,

Q. Nothing can exist in a natural state,

which can be called good or bad by common assent, since every man who is in natural state consults only his own advantage, and determines what is good or bad according to his own fancy and insofar as he has regard for his own advantage alone, and holds himself responsible to no one save himself by any law; and therefore sin cannot be conceived in a natural state, but only a civil state, which is decreed by common consent what is good or bad, and each one holds himself responsible to the state.

Q 1. Which one of the following statements best reflects the central idea of the passage given above?
(a) The conceptions of what is right or wrong exist due to the formation of a state.
(b) Unless a ruling authority decides as to what is right or wrong, no man would be morally right.
(c) Man is inherently immoral and selfish in a natural state.
(d) The idea of what is right or wrong is necessary for the survival of human species.

Question from UPSC Prelims 2021 CSAT Paper

Explanation : 

Q1: Correct Answer – (a) The conceptions of what is right or wrong exist due to the formation of a state.

Explanation –

(a) “The conceptions of what is right or wrong exist due to the formation of a state.” This option reflects the central idea of the passage that in a natural state, individuals determine what is good or bad according to their own fancy and sin cannot be conceived. It is only in a civil state where common consent decrees what is good or bad.

(b) “Unless a ruling authority decides as to what is right or wrong, no man would be morally right.” This option suggests that without a ruling authority to determine what is right or wrong, individuals would not be able to act morally. However, this idea is not explicitly stated in the passage.

(c) “Man is inherently immoral and selfish in a natural state.” This option suggests that individuals are inherently immoral and selfish when they are in a natural state. While the passage does mention that individuals consult only their own advantage in a natural state, it does not explicitly state that they are inherently immoral or selfish.

(d) “The idea of what is right or wrong is necessary for the survival of human species.” This option suggests that having an understanding of what is right and wrong is necessary for human survival. However, this idea is not mentioned in the passage.

Q. Nothing can exist in a natural state, Read More »

Q. Our cities are extremely vulnerable to climate change because of large concentrations of populations and poor infrastructure.

Q. Our cities are extremely vulnerable to climate change because of large concentrations of populations and poor infrastructure.

Moreover, population densities are increasing in them but we have not yet developed the systems to address climate change impacts. Our cities contribute to 65 percent of the GDP, but there are not enough facilities to cater to the needs of the people. It is important to address the issues of air quality, transport, etc., that are vital to identifying sustainable solutions. We need to involve citizens in city planning and create an ecosystem that meets the needs of people.

Q 1. Which among the following is the most logical and rational inference that can be made from the passage given above?
(a) Our cities need to have well-defined administrative set-up with sufficient autonomy.
(b) Ever increasing population densities is a hindrance in our efforts to achieve sustainable development.
(c) To maintain and develop our cities we need to adopt sustainability related interventions.
(d) Public-Private Partnership mode of development is the viable long-term solution for the infrastructure and sustainability problems of India.

Question from UPSC Prelims 2021 CSAT Paper

Explanation : 

Q1: Correct Answer – (c) To maintain and develop our cities we need to adopt sustainability related interventions.

Explanation – The passage discusses the vulnerability of cities to climate change due to large populations and poor infrastructure. It highlights the need to address issues such as air quality and transport in order to identify sustainable solutions. The most logical and rational inference that can be made from this passage is option c) : “To maintain and develop our cities we need to adopt sustainability related interventions.”

Q. Our cities are extremely vulnerable to climate change because of large concentrations of populations and poor infrastructure. Read More »