Question

A random number generator is selecting numbers in the range 1 through 50. What is the probability that the random number generator will select a number that is not multiple of 7

Answer 1

43/50

Explanation:

Use the complement rule to find this probability. The complement of this event is the event that the random number generator selects a number that is a multiple of 7. There are 7 multiples of 7 that the generator could possibly select, namely 7,14,21,28,35,42,49, so the probability that the generator will select a multiple of 7 is 750. The probability of the complement is 1−750=4350.

Answer 2

7,14,21,28,35,42,49 are all dividible by 7. That are 7 Numbers. However we are looking for All the Numbers that are not a multiple of 7.

So 50-7=43.

There are 43 Numbers which are not a multiple of 7.

So 43/50=0.86

The probability is 0.86 or a 86% chance that the generator will select a Number which is not a multiple of 7.