Probability

[swerve]

A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. What is the probability that a block picked at random from the box will be red?

A. 1/25
B. 1/12
C. 1/7
D. 1/5
E. 1/3

The OA is B

Source: GMAT Prep

[Brent@GMATPrepNow]

A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. What is the probability that a block picked at random from the box will be red?

A. 1/25
B. 1/12
C. 1/7
D. 1/5
E. 1/3

The OA is B

Source: GMAT Prep

There are 25 red blocks
There are 300 blocks in total (25 + 100 +175 = 300)

P(block is red) = (number of ways to select a red block)/(total number of outcomes)
= 25/300
= 1/12

Answer: B

Cheers,
Brent