Question

The average of some observations is A. If each observation is reduced by 4, what will be the new average?
1. A + 4
2. 2A
3. 4A
4. A - 4

Answer 1

Correct Answer - Option 4 : A - 4

Given:

Average = A

Each number is reduced by 4.

Formula used:

Average = Sum of observations/Number of observations

Calculation:

Let the number of observations be n.

Let the new average be x.

According to the question,

A = Sum of observation/n

⇒ Sum of observations = An

Each number is reduced by 4, then all numbers will be reduced by 4n.

According to the question,

x = (An - 4n)/n

⇒ x = (An/n) - (4n/n)

⇒ x = A - 4

∴ The new average is A - 4.