Question

What is the probability of getting at least one head when tossing two coins? { HH, TH, HT, TT }

Answer 1

3/4

Explanation:

the chance of getting a head is 1/2 or a tail is 1/2 in the first turn.

and the chance of getting a head is 1/2 or a tail is also 1/2 in the 2nd turn as well.

the possibilities are HH, TH, HT, TT

only three of these possibilities have at least one head (HH, TH, HT)

the possibility of scoring double heads is 1/4 (1/2 * 1/2)

the possibility of scoring a tail and head is 1/4 ( 1/2 * 1/2)

the possibility of scoring a head and then tail is also 1/4 (1/2 * 1/2)

adding all the possibilities (1/4 + 1/4 + 1/4) is 3/4