Question

What will be the value of the middle number if the average of 7 numbers in a group is 24, average of the first three numbers is 34 and that of the last three numbers is 21?
1. 3
2. 31
3. 4
4. 27

Answer 1

Correct Answer - Option 1 : 3

Given:

Average of 7 numbers in a group is 24

Average of the first three numbers is 34

Average of the last three numbers is 21.

Concept used:

Average × number + average × number + ….. = average of all × total number

Calculation:

Let the value of the middle number be ‘x’

34 × 3 + x + 21 × 3 = 24 × 7

⇒ 165 + x = 168

⇒ x = 3

∴ Middle number = 3