Question

A bag contains 50 balls numbered from 1 to 50. One ball is drawn at random. Find the probability that a drawn ball is a multiple of 5 or 7.

Answer 1

probability that ball is multiple of 5 = 5,10,15,20,25,30,35,40,45,50 = 10

probability that ball is multiple of 7 = 7,14,21,28,35,42,49 = 7

probability that ball is multiple of both 5 and 7 i.e. 35 = 1

therfore , probability that a drawn ball is a multiple of 5 or 7 = 10+7-1 = 16

ans. = 16.