Question

Final grades are often computed using weighted averages. For example, Fran's teacher uses the following: homework 10%, quizzes 20%, and tests 70%.
Fran has an average homework score of 92. Her quiz score average is 68, and her test score average is 81. What final grade can Fran expect?
A) 73.5
B) 75.5
C) 78
D) 79.5

Answer 1

To do this question, we need to multiply each of Fran's given grades by the corresponding percentage, and then add them all together.

We'll start with Fran's homework grade of 92. This grade is 10% of her final grade, so what we can do is turn the percentage into a decimal and then multiply it by her homework grade. To change a percentage into a decimal, we just need to divide the percentage by 100, which in this case would give us .1. Now we just have to do 92*.1 to get 9.2 as our first component.

Next, we'll do Fran's quiz grades. Her quiz score average is a 68, and it holds a weight of 20%. We have to change the percentage to a decimal again and then multiply it by her grade. 20% turns into .2, and .2*68 gives us a 13.6 as our second component.

Now all that's left is Fran's test grades. Her test average is an 81, and it holds a weight of 70%. Once again, we have to change the percentage to a decimal and multiply it by her grade. 70% turns into .7 and .7*81 gives us 56.7 as the final component of Fran's grades.

Finally, we just have to add all of the components together. 9.2 + 13.6 + 56.7 = 79.5, which is Fran's final grade, meaning that D) 79.5 should be your answer!<span />

Answer 2

92 x 0.1 + 68 x 0.2 + 81 x 0.7
= 9.2 + 13.6 + 56.7
= 79.5%