Hey guys I cant do this following question so thanks in advance if you could help!

A bag contains 2 red marbles, 5 white marbles and 3 black marbles. A game is played with a player randomly drawing one marble at a time from the bag with replacement, continuing until he obtains a red marble or a white marble. He wins if the last marble is white and loses otherwise.

(a) Find the probability that the player wins.

(b) Find the minimum value of n for which P(he draws at most n marble to win) is more than or equal to 0.7.