Question

Average of 11 number is 30 .if average of first 10 number is 22,then find the 11th number

Answer 1

let 11 numbers are x1 , x2 , x3......., x11




Average of 11 numbers = 30


x1 + x2 + x3+.......+x11/11 = 30


x1 + x2 + x3+.......+x11 = 330




Average of first 10 numbers = 22


x1+x2+x3+......+x10/10 = 22

x1 + x2 + x3 + ......... + x10 = 220.



11th number = sum of first 11 numbers - sum of first 10 numbers


11th number = 330 - 220

11th number = 110