Data Sufficiency

BTGModeratorVI wrote: ↑

Wed Mar 25, 2020 6:23 am

If R, S, and T are points on a line, and if R is 5 meters from T and 2 meters from S, how far is S from T ?

(1) R is between S and T.
(2) S is to the left of R, and T is to the right of R.

Answer: D
Source: Official Guide

Given: R, S, and T are points on a line, and if R is 5 meters from T and 2 meters from S
There are 4 possible scenarios that meet the above conditions:


Target question: How far is S from T?

Statement 1: R is between S and T.
When we check the 4 possible scenarios, we see that scenarios #2 and #3 meet the conditions of statement 1
For both scenarios, the answer to the target question is the distance from S to T is 7
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: S is to the left of R, and T is to the right of R.
When we check the 4 possible scenarios, we see that only scenario #2 meets the conditions of statement 2
For scenario #2, the answer to the target question is the distance from S to T is 7
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent