The average (arithmetic mean) of the even integers from 0 to 60 inclusive is how much greater than the average (arithmetic mean) of the even integers from 0 to 30 inclusive?	Choose the correct choice from the following choices:
A) 10
B) 15
C) 20
D) 25
E) 30
The sum of even numbers from 0 to N is 2 + 4 +...+ N   = 2(1 + 2 + ...+ N/2)   = 2(N/2)(N/2+1)/2 = (N/2)(N/2+1)   The average is (N/2)(N/2+1)/(N/2+1) = N/2   The average of the even numbers from 0 to 60 is  60/2= 
<gadget id="calculator"> 60/2</gadget>
<output>30</output>
30   The average of the even numbers from 0 to 30 is  30/2= 
<gadget id="calculator"> 30/2</gadget>
<output>15</output>
15   The answer is 15.
<result>B</result>
The average (arithmetic mean) of the even integers from 0 to 60 inclusive is how much greater than the average (arithmetic mean) of the even integers from 0 to 30 inclusive?