Question 663154
The average of x numbers is 15.
the total of the 15 original numbers = 15x
:
 If two of the numbers are each increased by y, the new average will be increased by how much?
15x+2y = total of x numbers now
Therefore
{{{(15x+2y)/x}}} = the new average
:
Find the difference in the averages
 {{{(15x+2y)/x}}} - 15 = {{{(15x+2y-15x)/x}}} = {{{2y/x}}} is the dif in average