Question

Trensie is flipping a weighted coin where the probability of landing on tails is 1/ 3 . If she flips the coin two times, what is the probability that she gets heads only once?

Answer 1

The total possibilities is still 4.
H H
H T <<<< 
T H <<<<
T T

The two that work are marked with <<<<

H T = 1/3 * 2/3 = 2/9
T H = 2/3 * 1/3 = 2/9



The total is 2/9 + 2/9 = 4/9
We should check this
1 heads = 4/9
2 heads = 1/9
2 tails = 4/9
4/9 + 4/9 + 1/9 = 1 It checks