A coin is tossed three times. Find the probability of each event.

a) at least two tosses come up tails.
b) at least one toss comes up heads.

PLEASE SHOW ALL WORK!

2 answers

a) 2/3
b) 1/3
There are only 8 possible outcomes:
HHH, HTT, THT, TTH, HHT, HTH, THH, TTT

Of those, there are 4 with at least two tails
a) prob = 4/8 = 1/2

b) There are 7 with at least one H, (only TTT has no heads)
so prob = 7/8