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Sat Oct 09, 2021 6:05 am

GMAT Paper Tests

Chan and Mieko drove separate cars along the entire length of a certain route. If Chan made the trip in 15 minutes, how many minutes did it take Mieko to make the same trip?

1) Mieko's average speed for the trip was 3/4 of Chan's average speed
2) The route is 14 miles long

OA A

Given: Chan and Mieko drove separate cars along the entire length of a certain route. Chan made the trip in 15 minutes.

Target question: how many minutes did it take Mieko to make the same trip?

Statement 1: Mieko’s average speed for the trip was 3/4 of Chan’s average speed.
If you aren't familiar with attari92's inverse proportion property, you can still solve the question.

Let d = the distance traveled
Let r = Chan's speed (in the miles per minute)
So, (3/4)r = Mieko's speed (in the miles per minute)
In other words, 3r/4 = Mieko's speed

time = distance/speed
So, from the given information, we can write: d/r = 15 (minutes)

This means Mieko's travel time = d/(3r/4)
= (d)(4/3r)
= 4d/3r
= (4/3)(d/r)
= (4/3)(15)
= 20
So, Mieko's travel time is 20 minutes
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: The route is 14 miles long
Since this statement provides no information about Mieko, there's no way to calculate Mieko's travel time
Statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent