solving minumum % needed to acheive a final grade of 85%

Question

I need a course grade of 85%

I have four test results to date

• quiz grade 85% which is 12.5% of the course grade

• quiz grade of 100% which is 12.5% of the course grade

• mid term grade of 72% which is 30% of the course grade

• project grade of 100% which is 5% of the course grade

What is the minimum score I need on my final exam which will be 40% of the course grade?

Answer 1

0.85(.125) + (.125) + .72(.30) + .05 + .4x = .85

Solve for x.

Answer 2

When solving for weighted averages you must add up all of the grades times their weight. To solve for an unknown value we will create an equation to solve for the unknown exam grade (x) that is equal to the desired grade average (85%).

Remember that when using percentages in equations, you must convert them to decimal form.

0.85(.125) + 1.00(.125) + 0.72(.30) + 0.05(1.00) + x(0.4) = 0.85

To solve for x:

• solve and combine all the known weighted percentages on the left
• subtract them from both sides
• divide out the weight of the final exam (0.40) to get x by itself

The answer you will get will be the exam grade (x) required to get an 85%. It will be in decimal form, so convert it into a percentage to get your final answer.