Correct Answer - Option 4 : 10
Given:
The average of ‘x’ number = 49
New average = increased by 2.5
Formula Used:
Sum of all numbers = Average of numbers × Number of terms
Calculation:
The sum of ‘x’ natural number = 49 × x
⇒ 49x
The new sum of ‘x’ natural numbers = 49x + 25
The new average of ‘x’ natural number = 49 + 2.5
⇒ 51.5
The new sum of ‘x’ natural number = New average × Number of natural numbers
⇒ 49x + 25 = 51.5 × x
⇒ 49x + 25 = 51.5x
⇒ 51.5x – 49x = 25
⇒ 2.5x = 25
⇒ x = 10
∴ The value of x is 10.