Question

A bag contains balls numbered 2 to 91 such that each ball bears a different number. A ball is drawn at random from the bag. Find the probability that:

1. It bears a 2-digit number.
2. It bears as a multiple of 1.

Answer 1

S = (2, 3, 4, ..., 91}

Total n(S) = 90

i. 2-digit no. = {10, 11, 12, ..., 91}

Total n(A) = 82

P(2 digit no.) = `(n(A))/(n(S))`

= `82/90`

= `41/45`

ii. Multiple of 1 = {2, 4, ..., 91} = 90

P(Multiple of 1) = `90/90`

= 1