Question

1. In a study of 82 young (under the age of 32) drivers, 39 were men who were ticketed, 11 were men who were not ticketed, 8 were women who were ticketed and 24 who were not ticketed. If one of the subjects is randomly selected, find the probability of getting a man or someone who was ticketed

2.Your sock drawer has nine folded pair of socks, with three pairs each of white, black, and blue. WHat is the probability, without looking in the drawer, that you will first select and remove a black pair, then select either a blue or white pair?

Answer 1

1) Total no of persons= n(S) = 82

n(Man) = 39+11 = 50, n(tickets) = 39+8 = 47, n(man and ticketed) = 39

So, n(Man or ticketed) = n(Man) + n(ticketed) - n(man and ticketed) = 50+47-39 = 58

So, P(Man or ticketed) = 58/82 = 0.7073

2) P(select and remove black pair) = P(choosing from 3 black out of total 9 pairs) = 3/9 = 1/3

After removing the black pair, socks remaining = (2Black pair & 6 Blue or White pair)

So, P( drawing blue or white pair now) = 6/8 = 3/4

Since we are doing both the work simultaneously, so

Required Probability = (1/3)•(3/4) = 1/4 = 0.25