Coin 1 comes up heads with probability 0.6 and coin 2 with probability 0.5. A coin is continually flipped until it comes uptails, at which time that coin is put aside and we start flipping the other one.

(a) What proportion of flips use coin1?
(b) If we start the process with coin 1what is the probability that coin 2 is used on the fifth flip?