Question

The probabilities of two students A and B coming to the school in time are 3/7 and 5/7 respectively. Assuming that the events, ‘A coming in time’ and ‘B coming in time’ are independent, find the probability of only one of them coming to the school in time. Write at least one advantage of coming to school in time. 

Answer 1

Let E₁ and E₂ be two events such that 

E₁ = A coming to the school in time. 

E₂ = B coming to the school in time. 

Here P (E₁) = 3/7 and P (E₂) = 5/7

⇒ P(bar E₁) = 4/7, P(bar E₂) = 2/7

P (only one of them coming to the school in time) = P(E₁)P(bar E₂) + P(bar E₁)P(E₂)

= 3/7 x 2/7 + 5/7 x 4/7 = (6 + 20)/49 = 26/49

Coming to school in time i.e., punctuality is a part of discipline which is very essential for development of an individual.