Question

an integer is chosen at random between 1 and 100.find the probability that it is divisible by 8. not divisible by 8

Answer 1

Hola there..

1) We can find total no. of integer between 1 and 100 that are divisible by 8 by using A.P.

So,
Series = 8, 16, 24......96
a = 8
an = 96
d = 8

an = a + (n - 1)d

=> 96 = 8 + (n - 1)8

=> 88/8 = n - 1

=> n = 12

So, possible outcome = 12
Total no. of outcome = 98
p(getting a no. divisible by 8) = 12/98
= 6/49

2) Total no. that are not divisible by 8 between 1 and 100 = 98 - 12 = 86

Possible outcome = 86
Total no. of outcome = 98

P(getting no. not divisible by 8) = 86/98

= 43/49

Hope this helps....:)

Answer 2

total number integers between 1 and 100 =98
a.probability that divisible by 8   P(E) =12/98=0.1224
b.probability that not divisible by 8=1-P(E)
                                                      =1-0.1224
                                                      =0.8756