Mike took 5 mock tests before appearing for the GMAT. In each mock test he scored 10 points more than the previous mock test. If he scored 760 on the GMAT and his average score for the mocks and the GMAT was 716.67, what was the difference in the score of his last mock and his GMAT score?  Choices.
A) 20
B) 32
C) 40
D) 50
E) 60
One way to do this would be weighted average method..   1) let the average of 5 mocks be x...   so take it as a mix of5 quantitites of xand1 quantity of 760resulting in an average of 716.67...   By alligation/weighted average..   the difference in 760 and 716.67 is 5/6 of difference of 760 and x..   760-716.67 = 5/6 * (760-x)   760-x= 43.33*6/5=52...   so x = 708..   the last of mock test will be 708+10+10=728...   so ans = 760-728= 
<gadget id="calculator">760-728</gadget>
<output>32</output>
32   32
<result>B</result>
Mike took 5 mock tests before appearing for the GMAT. In each mock test he scored 10 points more than the previous mock test. If he scored 760 on the GMAT and his average score for the mocks and the GMAT was 716.67, what was the difference in the score of his last mock and his GMAT score?