A school has only four classes that contain 10, 20, 30 and 40 students respectively. The pass percentage of these classes are 20%, 30%, 60% and 100% respectively. Find the pass % of the entire school.  Choose the correct choice from the following choices.
A) 56% B) 76% C) 34% D) 66% E) None of these
Solution: The number of pass candidates are 2+6+18+40= 
<gadget id="calculator">2+6+18+40</gadget>
<output>66</output>
66 out of total 100.   Hence,   Pass pecentage= 66%.   Answer: Option 66%
<result>D</result>
A school has only four classes that contain 10, 20, 30 and 40 students respectively. The pass percentage of these classes are 20%, 30%, 60% and 100% respectively. Find the pass % of the entire school.