Three unbiased coins are tossed. What is the probability of getting at most two heads?

Question:
Three unbiased coins are tossed. What is the probability of getting at most two heads?

[A].

3

4

[B].

1

4

[C].

3

8

[D].

7

8

Answer: Option D

Explanation:

Here S = {TTT, TTH, THT, HTT, THH, HTH, HHT, HHH}

Let E = event of getting at most two heads.

Then E = {TTT, TTH, THT, HTT, THH, HTH, HHT}.

P(E) =	n(E)	=	7	.
	n(S)		8