Can someone please explain how to do this problem?

Woodrow wins a tic-tac-toe game 65% of the time when he chooses the first square and 32% of the time when his opponent chooses the first square. The player who plays first is chosen by a coin toss. What is the probability that Woodrow wins a given game?

I think you subtract or add 32% to or from 65% but I'm not sure.

2 answers

Pr(winning) = sum of prob of the ways to win...
Pr= 1/2 * .65 + 1/2 * .32= you do it.
.5 * .65 + .5 *.32 = .325 + .16 = .485

check
probability other player wins
= .5 * .35 + .5*.68 = .515
sum = 1, good :)