Question

Suppose that three fair coins are flipped independently. what is the probability that exactly two of them come up heads?

Answer 1

The probability of the first 2 being heads and the next one being a tail

= (1/2)^3 = 1/8

2 heads and 1 tail can happen in 3 different ways:-

HHT HTH THH

So probability of 2 H and 1 T = 3 * 1/8 = 3/8 Answer