4 women visit some or all 7 temples situated in a city. find the probability that all four women visit exactly two temples .

The four women could visit from one to seven temples.So each woman could visit one of the temples from 7 temples in 7 ways (7c1) or visit two of the seven temples in 21 ways(7c2) and so on for upto a visit of all the seven temples.So the various possibilities add upto 127 ways for a woman.Each of the women could visit some or all temples in 127 ways.So the total possibilities for all the four women is 127^4.

Further each woman could visit two temples in 21 ways(7c2).Sofor four women the total ways are 21^4.

So the probability is 21^4/127^4.