Question

Parked in the lot beside a local grocery store are 2 red, cars 9 white cars, 3 black cars, 1 blue car, and 6 brown cars, all belonging to shoppers in the store. assuming the shoppers leave randomly, what is the probability that the first 2 cars to leave are white?

9/49
11/21
6/35
8/49

Answer 1

the answer is 6/35

Explanation:

Answer 2

Consider a more familiar sounding problem, which is exactly the same in terms of probability:

In an urn, there are 2 Red, 9 White, 3 Black, 1 Blue and 6 Brown marbles.

What is the probability of the first 2 picked marbles, being white, if we do dot replace the marbles.


i) the probability of the first pick to be white is 9/(2+9+3+1+6)=9/21=3/7

ii) the probability of the second pick to be white, after the first one was white is: (9-1)/(21-1)=8/20=2/5

The probability of the first 2 picks being white is (3/7)*(2/5)=6/35


Answer: 6/35