An integer is chosen at random between 1 and 100
An integer is chosen at random between 1 and 100. Find the probability that it is:
- divisible by 8
- not divisible by 8
Answer
Number of integers between 1 and 100: 2, 3 , 4, 5 , ..., 99
Total number of outcomes = 98
(i) Numbers which are divisible by 8 are: 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96
Favourable Outcomes = 12
Probability that integer is divisible by 8, P(E) = 12/98 or 6/49
(ii) Probability that integer is not divisible by 8
P(E') = 1 - probability that it is divisible by 8
= 1 - 6/49
= 43/49