Question

Five numbers has a mean of 12. When one (1) number is removed the mean is 11. What is the value of the number removed?

Answer 1

16

Explanation:

The mean of a group of values is calculated as

mean =
`(sum)/(count)`

Given 5 numbers with a mean of 12, then

`(sum)/(5)` = 12 ( multiply both sides by 5 )

sum = 60

let the number removed be x , then

`(60-x)/(4)` = 11 ( multiply both sides by 4 )

60 - x = 44 ( subtract 60 from both sides )

- x = - 16 ( multiply both sides by - 1 )

x = 16

The number removed was 16