Question

QUESTION 5

A friend has a 81% average before the final exam for a course. That score includes everything but the final,
which counts for 15% of the course grade. Give answers accurate to at least one decimal place.
a. What is the best course grade your friend can earn?
%
b. What is the minimum score your friend would need on the final to earn a 75% for the course?
%

Answer 1

• 83.85%
• 41%

Explanation:

a) We assume the best grade that can be earned on the final is 100%. Then the best course grade is ...

(0.85)(81%) +(0.15)(100%) = 68.85% +15% = 83.85%

__

b) For a course score of 75%, we need a final score such that ...

(0.85)81%) +(0.15)f = 75%

68.85% +0.15f = 75% . . . simplify a bit

0.15f = 6.15% . . . . . . subtract 68.85%

f = 41% . . . . . . . . divide by 0.15

The minimum final exam score for a course grade of 75% is 41%.