Question

Question #ffee6

Answer 1

First, we need to find the prime numbers between 10 and 20.

Explanation:

The numbers between 10 and 20 are:

`11, 12, 13, 14, 15, 16, 17, 18, 19`

First, we can eliminate the even numbers. Every even number other than `2` is a prime number because it is divisible by `2`. This leaves:

`11, 13, 15, 17, 19`

`15 = 3 xx 5` so it is not a prime number.

This leaves the remaining prime numbers as:

`11, 13, 17, 19`

The formula to find the mean of a set of numbers is:

`A= s/n` Where:

`A` is the average or mean, what we are looking for in this problem.

`s` is the sum of the numbers in the set. For this problem:
`s = 11 + 13 + 17 + 19 =60`

`n` is the number of numbers in the set. For this problem there are `4` numbers in the set.

Substituting and calculating `A` gives:

A = 60/4#

`A = 15`

The mean of the prime numbers between 10 and 20 is: `color(red)(15`