Correct Answer - Option 1 : 24
Given :
The average of three consecutive numbers is 27.
Calculation :
Let the first number be x
The second number = (x + 1)
The third number = (x + 2)
A.T.Q.
(x + x 1 + x + 2)/3 = 27
⇒ (3x + 3) = 27 × 3
⇒ 3x + 3 = 81
⇒ 3x = 78
⇒ x = 26
First number = 26
Second number = 27
Third number = 28
Now,
Each number is decreased by 3
First new number = 26 - 3 = 23
Second new number = 27 - 3 = 24
Third new number = 28 - 3 = 25
⇒ New average = (23 + 24 + 25)/3
⇒ New average = 72/3
⇒ New average = 24
∴ the required new average is 24
Short tricks :
If each number is decreased or increased by the given number the average will also decrease or increase by the given number.
Each number is decreased by 3 so, the average will also decrease by 3.
Given average = 27
Each number is decreased by 3
⇒ New average = 27 - 3
∴ The required new average is 24.
