Data Sufficiency Questions and Answers

Answer: C

Correct answer: Either 1 or 2 is sufficient

Statement 1 makes D the wife of X and Y her child, so X is Y’s father. Statement 2 says X is married to Y’s father, which would make X Y’s mother. Each statement alone determines the relationship, so either is sufficient - and the two happen to disagree on X’s sex, which the question does not ask about.

Answer: C

Correct answer: Either 1 or 2 is sufficient

From statement 1, R third to the left of Q and P second to the right of R gives the order R, P, S, Q, T reading left to right, so S is immediately right of P. From statement 2, T second to the right of P with Q immediately left of T gives R, P, Q, T with S filling the remaining place - and again S sits immediately right of P. Each alone fixes the arrangement.

Answer: D

Correct answer: Both 1 and 2 are sufficient

February 2004 was a leap year, so the dates run 1 to 29. Statement 1 alone leaves fourteen even dates; statement 2 alone leaves ten primes. Taken together, only one number is both even and prime - 2 - so the date is settled, and only by using both.

Answer: D

Correct answer: Neither 1 nor 2 is sufficient

Statement 1 tells us Y has one brother and statement 2 that X has one sister, but neither says that X and Y are related to each other at all, nor gives the sex of either. Even together they leave the relationship undetermined, since X’s sister need not be Y and Y’s brother need not be X.

Answer: D

Correct answer: Both 1 and 2 are sufficient

Statement 2 makes F’s mother the sister of M’s father, so F is a cousin of M. Statement 1 establishes that M and P are siblings, so M’s father is P’s father and F is therefore P’s cousin as well. Neither statement alone connects F to P, so both are required.

Answer: C

Correct answer: Either 1 or 2 is sufficient

The question asks how A is related to B, and since B is A’s brother the answer turns entirely on A’s sex. Statement 1 calls A the sister of C, and statement 2 makes A the wife of E; each establishes that A is female and therefore B’s sister. Either alone will do.

Answer: C

Since 8th to the left of 12th from the right is 20th from the right, so from 1, we know that Vishakha is 5th from left and 20th from right i.e. there are 4 children to the left and 19 to the right of Vishakha. So, there are (4 + 1 + 19) i.e. 24 children in the row.

From 2, Nisha is 7th from right and 18th from left end of the row.

So, there are (6 + 1 + 17) = 24 children in the row.

Answer: B

From 1, total number of doctors in town = (1/700 x N) , where N = total number of residents in town. But, the value of N is not known.

From 2, total number of doctors in town

= (Number of wards in town) x (Number of doctors in each ward)

= 16 x 16 = 256.

Answer: B

Correct answer: 2 alone is sufficient while I alone is not sufficient

Statement 2 places the sister’s birth on the third day of the week, Tuesday, and two days after Sahil’s, so Sahil was born on Sunday. Statement 1 relates Sahil’s birthday to Arun’s without fixing either to a day of the week, so it gives no answer on its own.

Answer: D

Correct answer: Both 1 and 2 are sufficient

Statement 1 gives 300 pages with 200 read before Sunday, leaving 100. Statement 2 says the last 40 were read on Monday, so 60 were read on Sunday. Statement 1 alone leaves the remaining 100 undivided between Sunday and Monday, and statement 2 alone gives no total, so both are needed.