Question

There are 4 black balls and 6 white balls in a box. Assume you pick one ball at a time, and the selection is without replacement. If you select 2 balls, what is the probability that none of them is black.

Answer 1

Given data

Black balls=4

White balls=6

Number of balls selected=2

Now we pick one ball at a time and no replacement

So the probability of getting none of them is black =1- probability of getting black

The probability of getting 1st ball black=4/10

The probability of getting 2nd ball black=3/9

The probability of getting two balls blacks is equal=(4/10)x(3/9)

=0.4x0.33

=0.132

Probability of getting none of them black is equal to =1-0.132

=0.868

The answer is 0.868