Question: A class is 40% boys. The rest are girls. Every boy in class gets an 80% on the math test. Every girl gets a 90%. What is the class average on the test? Think carefully first, then make a decision:
The class is 60% girls because 100 - 40 = 60. The class average is 86% because .4(80) + .6(90) = 86. So the answer is 86.