IIT JEE , AIEEE Forum - Mathematics , Algebra

manjotpahwa

A doctor is to visit a patient. From the past experience, it is known that the

probabilities that he will come by train, bus, scooter or by any other means of

transport are respectively

3 ,1, 1 and2

10 5 10 5 . The probabilities that he will be late

are

1,1and 1

4 3 12 if he comes by train, bus and scooter respectively, but if he comes

by other means of transport, then he will not be late. When he arrives, he is late.

What is the probability that he comes by train.

ans is 5/7????