Real Challenge 4.4.2.

1. When two fair coins are tossed, what is the probability of getting exactly one head?
sol
(h,h),(h,t),(t,h),(t,t)
==>2/4=1/2

Answer: 1/2

2. When four fair coins are tossed, what is the probability of getting exactly two heads?
sol
p(h=2)
=C(4,2)*(1/2)^4
=4!/(2!*2!)*(1/16)
=6/16
=3/8

Answer: 3/8