Probability

1. Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5?

i. 0.5

ii. 0.4

iii. 0.5333

iv. 0.45

Ans: iv

2. A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?

i. 10\21

ii. 11\21

iii. 2\7

iv. 5\7

Ans: i