Question

Question 3

Answer 1

Answer:

The best course grade your friend can earn is 0.867 = 86.7%.

The minimum score would your friend would need on the final to earn a 75% for the course is of 0.61 = 61%.

Step-by-step explanation:

This is a weighed average problem, in which we multiply each grade by its weight.

We have that:

In 70% of the course, the friend has a grade of 81%.

In the other 30%, he will have x.

What is the best course grade your friend can earn?

This will happen if he earns 100% = 1 on the final test. So

$G = 0.7*0.81 + 0.3*1 = 0.867$

The best course grade your friend can earn is 0.867 = 86.7%.

What is the minimum score would your friend would need on the final to earn a 75% for the course?

This is x, when the grade is 0.75. So

$0.75 = 0.7*0.81 + 0.3x$

$0.3x = 0.75 - 0.7*0.81$

$x = \frac{(0.75 - 0.7*0.81)}{0.3}$

$x = 0.61$

The minimum score would your friend would need on the final to earn a 75% for the course is of 0.61 = 61%.