Hello, it is a permutation / combination approach question, however, having thought about an hour i can't get any idea how it should be solved.
A coin is flipped n times, where n>=3
Find the number of ways to obtain
(i) exactly two heads
(ii) at least 2 heads
I am not asking for answers. I have the answers but I don't understand... I don't know how to understand the problem from the definition of permutation and combination.