The average of six numbers is 6. If 3 is subtracted from each of four of the numbers, what is the new average?
The average of 6 numbers is 6. This means that all 6 numbers have to add up to 36.
It doesn't matter what the numbers are, but in order to average out to 6, the sum of all the numbers divided by 6 has to equal 6.
The only thing that gives 6 when divided by 6 is 36.
Now, 3 is subtracted from 4 numbers, for a total of 12.
(36-12)/6 tells us our new average
4 is the new average.
You have given an excellent answer Ninja.
Perhaps you would like to include it in your new sample questions thread.