Algebra 1: Linear equation word problem?

A baseball player's batting average is the number of hits the player has divided by the number of at-bats. At the beginning of a game, a player has a batting average of .360. During a game, the player gets 3 hits during 5 at-bats, and his batting average changes to .375.

a) Write a system of linear equations that represent the situation.

b) How many at-bats has the player had so far?

c) Another player on the team has a batting average of .240 at the beginning of the same game. During the game, he gets 3 hits during 5 at-bats, and his batting average changes to .300. Has this player had more at-bats so far this season than the other player.

If you could show your work that would be great

PS. This isn't for a grade but it is a study question and I want to know how to do this before the test.