Question

An integer is chosen at random from the first 100 positive integers. Then the probability that the number chosen is divisible by 3 or 4 equals

Answer 1

The all numbers that we have are = 1, 2, 3,......100

The numbers divisible by 3 are = 3, 6, 9,....99 i.e. a total 33 numbers

The numbers divisible by 4 are = 4, 8, 12,....100 i.e. total 25 numbers

But if we combine these two sets of numbers, we will get some duplicate values

The duplicate values are actually the multiples of 3 x 4 i.e. 12

So, numbers divisible by 12 are = 12, 24,...96 i.e a total of 8 numbers

So,

Numbers which are divisible by 3 Or 4 are = 33 + 25 - 8 = 50

Probability that chosen number is divisible 3 or 4 is given by

Probability = 50 / 100

P = 1/2 or 0.5

Answer 2

Answer:

20. An integer is chosen at random from the first 1 to 100 integer then, the probability that this number will not be divisible by 5 or 8 is

(1 Point)

310310

710710

910910

110110