Question

A box contains 90 discs which are numbered from 1 to 90. If one discs is drawn at random from the box, find the probability that it bears (i) a two digit number (ii) a perfect square number (iii) a number divisible by 5.

Answer 1

I) a two digit number = 9/10

II) a perfect square = 1/10

III) a number divisible by 5 = 2/10

Total number of discs present in the box = 90

Number of two digit numbered discs present in the box = 81

Probability of getting a two digit number = 81/90 = 9/10

Number of discs with perfect square = 9

Probability of getting a perfect square = 9/90 = 1/10

Number of discs that have numbers which are divisible by 5 = 18

Probability of getting a number divisible by 5 = 18/90

= 2/10