The Averages 10% Increase Problem Solution is as follows :
1. I give you 10 positive numbers and ask you to calculate the average. Lets call that X . Suppose I now increase each of those numbers by 10% and ask you to recalculate. By how much will your average change ?
a. 20% decrease
b. 10% decrease
c. 10% increase
d.20% increase
The solution is given below :
EXPLANATION :
Consider any 10 positive numbers of your choice 
For this example, lets take the first 10 numbers
Say 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 .
So average will be (1+2+3+4+5+6+7+8+9+10)/10 = 5.5
Consider a 10% increase now to each of those numbers.
So new average will be
(1.1+2.2+3.3+4.4+5.5+6.6+7.7+8.8+9.9+11)/10 = 60.5/10 = 6.05
So if you now subtract 6.05 – 5.5 = 0.55 which is 10% of 5.5
This means that the average also increases by 10% . i.e the Answer is (c) 10% increase