Question

a group of 4 numbers have an average of 15, three of the numbers are 18,11 and 25. what is the other number?? ​

Answer 1

6

Explanation:

The average of a set of numbers is their sum divided by their number. This fact lets us write an equation to find the missing number.

Setup

Let x represent the missing number. The average of the 4 numbers is ...

(x +18 +11 +25)/4 = 15

Solution

Multiplying by 4 gives ...

x +54 = 60

Subtracting 54, we find the missing number:

x = 6

The other number is 6.