Question

A bag contains 7 black 6 white and 5 red balls. If two balls are draw randomly then what is probability of getting bith of red

Answer 1

We can use Permutations and Combinations to solve this:

No of ways of selecting 2 red balls=5C2=10

Total no of ways to select 2 balls=18C2=153(in total there are 18 balls).

So the probability of picking 2 red balls=10/153=0.0653.

Similarly for probability of picking 2 black balls: 7C2/18C2=21/153=0.1372.

:)