Question

Suppose a fair coin is tossed until a head is obtained, and that this experiment is performed independently a second time. What is the probability that the second experiment requires more tosses than the first experiment?

Answer 1

Answer:

2/3

Step-by-step explanation:

Make X and Y represent the numbers of tosses.

The probability that X=n is 1/2n,

the probability that X=n and Y=n is 122n. Sum up, 1 to ∞.

We get 1/3.

We have 2/3 divided squarely between X>Y and X<Y.