Three fair coins are tossed List the 8 simple outcomes for t

Three fair coins are tossed. List the 8 simple outcomes for three fair coins. Find the probability of getting at least one head. Find the probability of getting exactly two heads.

Solution

Let H and T denote respectively head and tail.

All possible outcomes in tosses of three coins are:

(HHH),(HHT),(HTH),(HTT),(THH),(THT),(TTH),(TTT).

P(Getting at least one head) = 7/8 (Since in 7 outcomes in the above 8 possible outcomes at least one head is obtained.)

P(Getting exactly two heads) = 3/8    (Since in 3 outcomes in the above 8 possible outcomes exactly two heads are obtained.)