AP EAMCET Engineering 22 Apr 2019 Shift 1 Paper

Suppose that a bag A contains n red and 2 black balls and another bag B contains 2 red and n black balls. One of the two bags is selected at random and two balls are drawn from it at a time. When it is known that the two balls drawn are red, if the probability that those two drawn are from bag A is

6

7

, then n =