Question

During each of the first three quarters of the school year, Melissa earned a grade point average of 2. 1, 2. 9, and 3. 1. What does her 4th quarter grade point average need to be in order to raise her grade to a 3. 0 cumulative grade point average?

Answer 1

Answer: 3.9

Step-by-step explanation:

(2.1 + 2.9 + 3.1) / 3=2.7

(3.0 x 4 quarters)

(2.7 x 3 quarters)

(8.2 + x) / 4 = 3.0

Solving for x:

8.1 + x = 12

x = 3.9

Therefore, Melissa needs to earn a grade point average of 3.9 in the fourth quarter to raise her cumulative grade point average to 3.0

Answer 2

Answer: 3.9

Explanation:

She should have 4 grades that average to 3.0

2.1

2.9

3.1

x let's call last number x

Average = (2.1 +2.9 +3.1 +x) / 4 >She wants 3.0 so Average =3.0

3.0 = (2.1 +2.9 +3.1 +x) / 4 >Multiply both sides by 3

12. 0 = (2.1 +2.9 +3.1 +x) >combine like terms

12.0 = 8.1 +x >Subtract 8.1 from both sides

x = 3.9

She needs a 3.9 for the 4th quarter to have a 3.0 average