could you check the first question again!

2. Two coins are flipped. One is fair with head on one side and tail on other. The second coin is tricky one - it has 2 tails on both sides. She picks one at random and flips it.

(a) Probability it lands heads up?

(1/2)*(1/2) = 1/4

(b)it lands tails up, probability she picked up fair coin?

(1/2)/(3/4) = 2/3