Question

Suppose 5 men and 7 women are on a crowded elevator. At the next floor, four people get off the elevator. Find the probability that exactly one woman left the elevator.

0.141


0.859


0.035


0.143

Answer 1

0.141

Explanation:

There are ₇C₁ ways to choose 1 woman from 7.

There are ₅C₃ ways to choose 3 men from 5.

There are ₁₂C₄ ways to choose 4 people from 12.

So the probability is:

₇C₁ ₅C₃ / ₁₂C₄

7 × 10 / 495

0.141