GMAT Data Sufficiency Sample Questions

Defining the margins of problems

GMAT DATA SUFFICIENCY

GMAT Data Sufficiency is a very unique question type among GMAT questions and test prep in overall. Unlike a typical problem where you have to directly answer a question, a data sufficiency problem requires that you determine whether a question can be conclusively answered by analyzing two pieces of evidence, or statements, that are 100% true (re-read the underlined to save yourself a lot of time in the next weeks and months as you prepare), first separately, then combined.

Consider the detailed video and example below.

GMAT Data Sufficiency Rules

Data Sufficiency sample problem

Is the positive integer x even?

(1) When you divide the integer x by 4, the remainder is not 0.

(2) When you divide the integer x by 2, the remainder is not 0.

A – STATEMENT (1) ALONE is sufficient, but STATEMENT (2) alone is not sufficient.

B – STATEMENT (2) ALONE is sufficient, but STATEMENT (1) alone is not sufficient.

C – BOTH STATEMENTS TOGETHER are sufficient, but NEITHER ALONE is sufficient.

D – EACH STATEMENT ALONE is sufficient.

E – NEITHER STATEMENT ALONE NOR TOGETHER are sufficient.

Show answer

The correct answer is B.
According to statement (1), when you divide the integer x by 4, the remainder is not 0. This is inconclusive because:
I can identify integers that are odd that satisfy that statement, but also even integers that satisfy the statement. For example:
(i) when the ODD integer 15 is divided by 4, the remainder is not 0.
(ii) when the EVEN integer 6 is divided by 4, the remainder is not 0.
For a statement to be declared sufficient, it must allow us to conclusively say YES x is surely even, or NO x is surely not even.
Statement (2) is conclusive because any even integer is divisible by 2.