Question

Average of 5 numbers in a group is 30. Given that the average of the first two numbers is 35 and the middle number is 34. Find the average of last two numbers.
1. 23
2. 25
3. 23.5
4. 20

Answer 1

Correct Answer - Option 1 : 23

Given:

Average of 5 numbers in a group is 30

Average of the first two numbers is 35

Middle number is 34

Concept used:

Sum of all observations = Average × Total number of observations

Calculation:

Let the average of last two numbers be ‘x’

35 × 2 + 34 + x × 2= 30 × 5

⇒ 70 + 34 + 2x = 150

⇒ 2x = 46

⇒ x = 23

∴ Average of last two numbers is 23