Question

Lauryn has earned the following score on her Ap physics exams : 24/30, 17/20, 34/40, 50/50 and 72/80 what score must lauryn earn on her sixth exam in order to maintain at least an 85% average?Lauryn must earn at least a ----- percent.If lauryn score a 75% on her sixth exam will she keep her average of at least an 85 type YES or NO .what would lauryn's average score be if she scores a 85% on the sixth exam?

Answer 1

First, we have to transform the fractions into percentage as follows:

24/30*100 = 80%

17/20*100 = 85%

34/40*100 = 85%

50/50*100 = 100%

72/80*100 = 90%

Let's call x to the score on her sixth exam. The average of the six exams is:

(80 + 85 + 85 + 100 + 90 + x)/6

This average must be equal to or greater than 85, then

(80 + 85 + 85 + 100 + 90 + x)/6 ≥ 85

80 + 85 + 85 + 100 + 90 + x ≥ 85*6

80 + 85 + 85 + 100 + 90 + x ≥ 510

x ≥ 510 - (80 + 85 + 85 + 100 + 90)

x ≥ 70

Lauryn must earn at least a 70 percent.

If Lauryn score a 75% on her sixth exam will she keep her average of at least an 85. YES, because its greater than 70%

If she scores a 85% on the sixth exam, Lauryn's average score would be

Average = (80 + 85 + 85 + 100 + 90 + 85)/6 = 87.5%