The average of ten numbers is 18. If one number is removed, then the average becomes 16, then what is the removed number?
1). 36
2). 40
3). 48
4). 52
Average = sum of 10 numbers/10
⇒ 18 = sum of 10 numbers/10
⇒ Sum of 10 numbers = 180
And, Average when the number is removed = sum of 9 numbers/9
⇒ 16 = sum of 9 numbers/9
⇒ Sum of 9 numbers = 144
∴ Number removed = 180 - 144 = 36