Q. Two Statements are given followed by two Conclusions:
Statements: All numbers are divisible by 2. All numbers are divisible by 3.
Conclusion-l All numbers are divisible by 6. Conclusion-II All numbers are divisible by 4.
Which of the above Conclusions logically follows/follow from the two given Statements? (a) Only Conclusion-l (b) Only Conclusion-II (c) Neither Conclusion-I nor conclusion-Il (d) Both Conclusions-I and Conclusion-II Correct Answer: (a) Only Conclusion-l
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
Conclusion-I: All numbers are divisible by 6
Analysis:
– The numbers are divisible by both 2 and 3 – 6 is the least common multiple (LCM) of 2 and 3 – Any number divisible by both 2 and 3 must be divisible by their LCM (6) – Therefore, Conclusion-I is TRUE
Conclusion-II: All numbers are divisible by 4
Analysis:
– Just because a number is divisible by 2 and 3 doesn’t mean it’s divisible by 4 – Example: 6 is divisible by both 2 and 3, but not by 4 – Therefore, Conclusion-II is FALSE
Q. A man walks down the backside of his house straight 25 meters, then turns to the right and walks 50 meters again; then he turns towards left and again walks 25 meters. If his house faces to the East, what is his direction from the starting point?
The man starts at the back of his house facing East. He then walks 25 meters straight down the backside of his house. Since he is walking away from the house and the house faces East, he is now facing West.
He then turns to his right and walks 50 meters. Since he was originally facing West and turned right, he is now facing North.
Finally, he turns left and walks another 25 meters. Since he was originally facing North and turned left, he is now facing West again.
So from his starting point at the back of his house, the man has walked in a rectangular path and ended up to the North-West of where he started. So the correct answer is (d) North-west.
Q. Two Statements S1 and S2 are given below with regard to two numbers followed by a Question:
S1: Their product is 21. S2: Their sum is 10.
Question: What are the two numbers? Which one of the following is correct in respect of the above Statements and the Question? (a) S1 alone is sufficient to answer the Question. (b) S2 alone is sufficient to answer the Question. (c) S1 and S2 together are sufficient to answer the Question, but neither S1 alone nor S2 alone is sufficient to answer the Question. (d) S1 and S2 together are not sufficient to answer the Question. Correct Answer: (c) S1 and S2 together are sufficient to answer the Question, but neither S1 alone nor S2 alone is sufficient to answer the Question.
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
Product is 21 and Sum is 10
Statement S1: xy = 21 Statement S2: x + y = 10
Solution Steps: 1. From S1: y = 21/x
2. Substitute this in S2: x + 21/x = 10
3. Solve for x: Multiply both sides by x: x² + 21 = 10x Rearrange: x² – 10x + 21 = 0 Factor: (x – 7)(x – 3) = 0 Therefore: x = 7 or x = 3
4. Find corresponding y values: When x = 7: y = 21/7 = 3 When x = 3: y = 21/3 = 7
5. The two numbers are 3 and 7
Conclusion: Neither statement alone is sufficient, but together they give us the unique solution. Therefore, answer is (c): S1 and S2 together are sufficient to answer the Question.
Q.Two Statements S1 and S2 are given below followed by a Question:
S1: n is a prime number. S2: n leaves a remainder of 1 when divided by 4.
Question: If n is a unique natural number between 10 and 20, then what is n?
Which one of the following is correct in respect of the above the Statements and Question? (a) S1 alone is sufficient to answer the Question. (b) S2 alone is sufficient to answer the Question. (c) S1 and S2 together are sufficient to answer the Question, but neither S1 alone nor S2 alone is sufficient to answer the Question. (d) S1 and S2 together are not sufficient to answer the Question. Correct Answer: (d) S1 and S2 together are not sufficient to answer the Question.
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
Analysis of Statement S2: – When a number n is divided by 4, remainder is 1 – Such numbers can be written as: n = 4k + 1 (where k is an integer) – Numbers between 10 and 20 that fit this pattern are: 11, 13, 15, 17, 19
Analysis of Statement S1: – Number n must be prime – From the above list, only 11 and 17 are prime numbers – So S1 alone gives us two possibilities: n = 11 or n = 17
Combined Analysis: – Both statements together still give us two possibilities – Both 11 and 17: Are prime numbers (satisfying S1) Leave remainder 1 when divided by 4 (satisfying S2)
Conclusion: Therefore, answer is (d): S1 and S2 together are not sufficient to determine a unique value of n.
Q. Two Statements S1 and S2 are given below with regard to four numbers P, Q, R and S followed by a Question:
S1: R is greater-than P as well as Q. S2: S is not the largest one.
Among four numbers P, Q, R and S which one is the largest? Which one of the following is correct in respect of the above Statements and the Question? (a) S1 alone is sufficient to answer the Question. (b) S2 alone is sufficient to answer the Question. (c) S1 and S2 together are sufficient to answer the Question, but neither S1 alone nor S2 alone is sufficient to answer the Question. (d) S1 and S2 together are not sufficient to answer the Question. Correct Answer: (c) S1 and S2 together are sufficient to answer the Question, but neither S1 alone nor S2 alone is sufficient to answer the Question.
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
S1: R is greater than both P and Q
– This alone is not enough to determine the largest number – R could be either largest or second largest
S2: S is not the largest number
– This alone is not enough to determine the largest number – S could be second largest, third largest, or smallest
Combined Analysis: When we use both statements together: 1. R is greater than P and Q (from S1) 2. S is not the largest (from S2) 3. Since R is greater than P and Q, and S cannot be largest, R must be the largest number
Conclusion: Therefore, answer is (c): S1 and S2 together are sufficient to answer the Question, but neither S1 alone nor S2 alone is sufficient.
Q. A family of two generations consisting of six members P, Q, R, S, T and U has three males and three females.
There are two married couples and two unmarried siblings. U is P ‘s daughter and Q is R ‘s mother – in – law. T is an unmarried male and S is a male. Which one of the following is correct? (a) R is U’s husband. (b) R is S’s wife. (c) S is unmarried. (d) None of the above Correct Answer: (b) R is S’s wife.
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
A family of two generations consisting of 6 members
From the given information: – U is P’s daughter – Q is R’s mother-in-law – T is an unmarried male – S is a male – There are two married couples in the family
Analysis: 1. Since Q is R’s mother-in-law, R must be married to one of Q’s children 2. We know T is unmarried and S is male 3. With two married couples and T being unmarried, S must be married 4. Since R is married to Q’s child and S is married, R must be S’s wife
Q. Two statements S1 and S2 are given below followed by a Question:
S1: There are not more than two figures on any page of a 51-page book. S2: There is at least one figure on every page.
Question: Are there more than 100 figures in that book? Which one of the following is correct in respect of the above Statements and the Question? (a) Both S1 and S2 are sufficient to answer the Question, but neither S1 alone nor S2 alone is sufficient to answer the Question. (b) S1 alone is sufficient to answer the Question. (c) S1 and S2 together are not sufficient to answer the Question. (d) S2 alone is sufficient to answer the Question. Correct Answer: (c) S1 and S2 together are not sufficient to answer the Question.
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
PROBLEM: Can we determine if there are more than 100 figures in the book?
GIVEN: Statement S1: Not more than 2 figures on any page; 51 pages Statement S2: At least 1 figure on every page
Q. Consider the following arrangement that has some missing letters:
abab_b_bcb_dcdcded_d The missing letters which complete the arrangement are (a) a, b, c, d (b) a, b, d, e (c) a, c, c, e (d) b, c, d, e Correct Answer: (c) a, c, c, e
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
The pattern is a b a b a / b c b c b / c d c d c /d e d e d