the mean of 5 number is 18 if one number is excluded, their mean is 16 .find the excluded number

The mean of 5 numbers is 18

therefore the sum of 5 observations is 90

let the excluded number be x

therefore the sum of 4 observations is 90 - x

now,

the new mean = 16(given)]

therefore the sum of observations excluding that number = 16*4

  = 64

A/Q

90 - x = 64

-x = -26

x = 26

therefore the excluded number is 26