Question

The mean of 5 numbers is 27. If one more number is included, then the mean is 25. Find the included number.

Answer 1

We have:
Mean = Sum of five numbers $÷$ 5
⇒ Sum of the five numbers = 27 x 5 = 135.

Now, New mean = 25
25 = Sum of six numbers ​$÷$ 6
⇒ Sum of the six numbers = 25 x 6 = 150.

The included number = Sum of the six numbers - Sum of the five numbers
⇒​The included number = 150 - 135
⇒The included number = 15.