Question 1:
In a cricket math, a bats woman hits a boundary 6 times out of 30 balls she plays. Find the probability that she did not hit a boundary.
Solution 1:
Number of times the bats woman hits a boundary = 6
Total number of balls played = 30
∴ Number of times that the bats woman does not hit a boundary = 30 − 6 = 24
P (she does not hit a boundary) = Number of times she does not hit boundary / Total number of balls played
= 24/30
= 4/5
Question 2:1500 families with 2 children were selected randomly, and the following data were recorded: Compute the probability of a family, chosen at random, having
| Number of girls in a family | 2 | 1 | 0 |
| Number of families | 475 | 814 | 211 |
(i)2 girls
(ii)1 girl
(iii)No girl
Also check whether the sum of these probabilities is 1.
Solution 2:
Total number of families = 475 + 814 + 211 = 1500
(i)Number of families having 2 girls = 475
P1 (a randomly chosen family has 2 girls) = Number of families having 2 girl / Total number of families
= 475/1500
= 19/60
(ii)Number of families having 1 girl = 814
P2 (a randomly chosen family has 1 girl)= Number of families having 1 girl / Total number of families
= 814/1500
= 407/750
(iii)Number of families having no girl = 211
P3 (a randomly chosen family has no girl) = Number of families having no girl / Total number of families
= 211/1500
Sum of all these probabilities= 19/60 + 407/750 + 211/1500
= 1500/1500
=1
Therefore, the sum of all these probabilities is 1.
