The average (arithmetic mean) of the even integers from 0 to 120 inclusive is how much greater than the average (arithmetic mean) of the even integers from 0 to 60 inclusive?
Choose the correct choice:
A) 10	B) 15	C) 20	D) 30	E) 60
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 120 is  120/2= 
<gadget id="calculator"> 120/2</gadget>
<output>60</output>
60   The average of the even numbers from 0 to 60 is  60/2= 
<gadget id="calculator"> 60/2</gadget>
<output>30</output>
30   The answer is 30.
<result>D</result>
The average (arithmetic mean) of the even integers from 0 to 120 inclusive is how much greater than the average (arithmetic mean) of the even integers from 0 to 60 inclusive?