Question

the mean of 5 numbers is 20. if one no. is excluded, mean of remaing number becomes 23 find the excluded no.

Answer 1

let numbers are=a,b,c,d and e
mean =20
a+b+c+d+e/5 =20
a+b+c+d+e=100
then let excluded no. is =a
so b+c+d+e/4=23
b+c+d+e=92
so a+92=100
a=100-92=8

Answer 2

ANSWER........................,

The mean of 5 number = 20

The sum of 5 number = 5 × 20 = 100

If one number is excluded ,

Then mean of 4 number = 23

Sum of 4 number =4 × 23 = 92

∴excluded number = 100 - 92 = 8