Question

A box contains 19 cards number 1 to 19 A card is drawn at random from the box find the probability that the number on the Drawn card is

A) divisible by 3 or 5
B) neither divisible by 3 nor by 5

Answer 1

p(div by 3) = 6/19

p(div by 5) = 3/19

p(div by 3 and 5) = 1/19

p(neither div by 3 nor by 5) = 8/19

Answer 2

Number of disc = 90

p (div by 3) = 6/19

p (div by 5) = 3 / 19

p (div by 3 and 5) = 1 / 19

p (neither div by 3 nor by 5) = 8 / 19

Number of two digit numbers in the disc = 10, 11, 12, 13, .....90

With counting the number of 2 digits numbers that includes  10, 11, 12, 13, .....90