if tests are 80% of the grade and homework is 20% of the grade and the test average is 87% and the homework average is 100%, what is the final grade?

Question

the 87% is on 4 tests and there are 2 tests left.  What does the student need to get on the 2 tests to average out a 90?

Answer 1

Add the weighted test and homework grades.  Since the test average is worth 80%, its weight is 0.80.  Similarly, since the homework average is worth 20%, its weight is 0.20.  The final grade is

 

0.80(87%) + 0.20(100%) = 89.6%

Answer 2

This is a WEIGHTED AVERAGE situation:

 

W.A. = 0.8(total on tests) + 0.2(total on HW)  where the two totals mentioned as each on a scale of 0-100.

Then the W.A. (weighted average) value is also on a 0-100 scale.