Question

A two digit number is to be formed from the digits 0,1,2,3,4, without repetition of the digits. Find the probability that the number so formed is a prime number.

Answer 1

The sample space,

• = {10,12,13,14,20,21,23,24,30,31,32,34,40,41,42,43}

∴ n( *) = 16

Let A be the event that the number is a prime.

∴ A = {13,23,31,41,43}

∴ n(A) = 5

∴ P(A) = n(A) / n( *) =5 /16