The average of 10 numbers is X and one of these numbers is 70. If 70 is replaced with 30, then what will be the new average?
Show answer & explanation
Correct answer: A
Explanation
Given:
Average of 10 numbers = X
One number = 70, New number = 30
According to the formula:
Sum = Average × Number
Total Sum = 10X
New Sum = 10X − 70 + 30 = 10X − 40
New Average = (10X − 40)/10
= X − 4