The average of a set of 10 numbers is 15. If one number is removed the average of the remaining numbers is 16. What is the value of the number removed?
If the average of 10 numbers is 15, we can express that as
x/10 = 15.
x, therefore, equals 150.
If one number is removed and the resulting average is 16, we can express that as
x/9 = 16.
Here, x equals 144.
144 is 6 less than 150, so the answer is 6.
source: majortests.com
