SOLUTION: Aaron and Jonathan take turns shooting a free throw, with Aaron going first. Whoever makes the first shot wins. The game continues until someone makes the shot. Aaron has a 40% ch

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Question 1145662: Aaron and Jonathan take turns shooting a free throw, with Aaron going first. Whoever makes the first shot wins. The game continues until
someone makes the shot. Aaron has a 40% chance of making a free throw, while Jonathan has a 50% chance. What is Aaron’s chance of
winning the game?

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


P(Aaron wins on his first shot) = 40% = 2/5

P(Aaron wins on his second shot) = (3/5)*(1/2)*(2/5) = 3/25
(Aaron misses on his first, probability 3/5; then Jonathan misses on his first, probability 1/2; then Aaron makes his second shot probability 2/5)

P(Aaron wins on his third shot) = (3/5)*(1/2)*(3/5)*(1/2)*(2/5) = 9/250

etc., etc., etc.....

The sum of the probabilities is a geometric progression with first term 2/5 and common ratio (3/5)*(1/2) = 3/10.

The probability that Aaron wins is the sum of that infinite geometric progression:

%282%2F5%29%2F%281-%283%2F10%29%29+=+%284%2F10%29%2F%287%2F10%29+=+4%2F7