Question

The mean of 10positive numbers is 16 when another number is added the mean is 18 . Find the number added?

Answer 1

number added is 38

Explanation:

mean is calculated as

mean =
`(sum)/(count)`

when the count is 10 the mean is 16 , then

`(sum)/(10)` = 16 ( multiply both sides by 10 )

sum = 160

let the number added be x then mean is 18 when count is 11, so

`(160+x)/(11)` = 18 ( multiply both sides by 11 )

160 + x = 198 ( subtract 160 from both sides )

x = 38

the number added is 38