Data Sufficiency

AAPL wrote:Princeton Review

A jar contains only green pencils and red pencils. If the jar contains a total of 225 pencils, what percentage of the pencils are green?

1. The jar contains 75 red pencils.
2. The jar contains twice as many green pencils as red pencils.

OA D

Target question: What percentage of the pencils are green?

Given: The jar contains only green pencils and red pencils.

Statement 1: The jar contains 75 red pencils.
If 75 of the 225 pencils are red, then the remaining 150 pencils are GREEN.
150/225 = 2/3 = 66 2/3%, so the answer to the target question is 66 2/3% of the pencils are green
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: The jar contains twice as many green pencils as red pencils.
Let R = # of red pencils
So 2R = # of green pencils
We have a total of 225 pencils, so we can write: R + 2R = 225
Solve to get R = 75, which means there are 75 red pencils
If 75 of the 225 pencils are red, then the remaining 150 pencils are GREEN.
150/225 = 2/3 = 66 2/3%, so the answer to the target question is 66 2/3% of the pencils are green
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D


Cheers,
Brent