Question

Urn I contains 2 red balls and 2 white balls. Urn II contains 13 white balls. A ball is selected at random from urn I and placed in urn II. Then a ball is selected at random from urn II. What is the probability that the second ball is​ white?

Answer 1

15/17 Because there is a 13/13 chance but then you put a ball in from Urn 1 and that is 2/4. Also, 13/13 plus 2/4 = 15/17