Hey sharmala.

First you need to find the probabilities. We know that the sum of all probabilities has to equal 1 and you have four probabilities where p1 + p2 + p3 + p4 = 1, but you have a relationship to link all these together.

Also since A contains two events the probability of A is P(A) = P(X=1 OR X=3).

I'll wait for you to make an attempt to solve the problem and give some hints but I need your feedback on what your thinking and what you have tried.