Question

The average of 10 numbers is 42. If one number is excluded, the average becomes 35. The excluded number is ;
1. 105
2. 100
3. 115
4. 90

Answer 1

Correct Answer - Option 1 : 105

Given:

The average of 10 numbers is 42

After excluding one number the average becomes 35.

Formula used:

Average = total sum of observations/ number of observations

Calculation:

The average of 10 number = 42

⇒ Total sum of numbers = 42 × 10

⇒ 420

⇒ After excluded 1 number average = 35

⇒ Sum of 9 numbers = 35 × 9

⇒ 315

Excluded number = 420 - 315 = 105

∴ The value of excluded number is 105.