Each of A and B tosses two coins. What is the probability that they get equal number of heads ?

Explanation

Let X be number of heads obtained by A and Y be number of heads obtained by B.
(n=3 and `p=1/2`)
`therefore` P(X=0) P(Y=0)+P(X=1) P(Y=1)+P(X=2) P(Y=2)+P(X=3) P(Y=3)
`=[""^3C_0(1/2)^3]^2+[""^3C_1(1/2)^3]^2+[""^3C_2(1/2)^3]^2+[""^3C_2(1/2)^3]^2`
`= (5/16)`