The average of 10 numbers is 30. When one number is replaced by 50, the average increases by 2. Find the number that was replaced.

Explanation

​ Information Given: Average of 10 numbers = 30 New average = 30 + 2 = 32 One number replaced by 50 Concept/Formula Used: Sum = Average × Number of terms Change in sum = New sum − Old sum www.freshersnow.com Explanation: Original sum = 10 × 30 = 300 New sum = 10 × 32 = 320 Increase in sum = 320 − 300 = 20 This increase is due to replacing a number by 50 So, 50 − original number = 20 Original number = 50 − 20 = 30