Question

The mean of six numbers is 23. If one of the numbers is excluded, the mean of the remaining numbers is 20. Find the excluded number.

Answer 1

It is given that

Mean of six numbers = 23

So we get the sum of six numbers = 23 (6) = 138

It is given that

Mean of five numbers = 20

So we get the sum of five numbers = 20 (5) = 100

We know that

Excluded number = sum of six numbers – sum of five numbers

By substituting the values

Excluded number = 138 – 100 = 38

Therefore, the excluded number is 38.