Question

An integer is chose at random between 1&100 find the probability , divisibal by 8¬ divisible by8

Answer 1

Number of integers between 1 and 100 : 2, 3 , 4, 5 , .....99

so, sample space { or total outcomes } = 98

So, you can say total number of sample space , n(S) = 98

Now , numbers , which are divisible by 8 are : 8 , 16 , 24 , 32, 40 , 48 , 56, 64, 72 , 80, 88 , 96

So, total number which are divisible by 8 = 12

So, number of possible event , n(E ) = 12

Now, probability that it is divisible by 8 , P(E) = n(E)/n(S) = 12/98 = 6/49

P(divisible by 8) = 6/49

Probability that it is not divisible by 8 , P(E') = 1 - probability that is is divisible by 8,P(E)

E.g., P( not divisible by 8) = 1 - 6/49 = (49 - 6)/49 = 43/49