Helpful for: MBA Applicants Read Time: 6 minutes Quick Facts:
- A great strategy to tackle data sufficiency questions is to eliminate all options until you have only one answer left.
- The first step is to analyze the prompt and break it down into parts, gathering as much information as possible from it. All the information you need to answer correctly is in the prompt. Eliza shares an example problem:
The difference between Simon and Gary’s age is twice as much as the difference between Simon and Chris’s age. If Simon is the oldest, what is the average (arithmetic mean) of all three?
(1) Gary is 27 (2) Chris is 31
- The next step is to put the prompt into an equation: S-G=2(S-C) which when multiplied out results in S=2C-G
- From this, we can conclude that two numbers will get us the average.
- When substituting S in the average equation, the G’s end up cancelling out, and we know that we need Chris’ age to find out the average.
- The simplest and final step is to use process of elimination. In the problem above, (1) is of no use since we still need either age, however the information give in (2) is sufficient.
- Make sure you plug one equation into the other, otherwise you can falsely assume that you need both options to solve the problem.
For more on the topic, read GMAT Tutorials: GMAT Quant – Data Sufficiency (Video).
Source: Best GMAT Prep Course