Question

Kelly’s first four test grades of the period were 80, 72, 96, and 88. Which inequality represents the grades she can earn on the fifth test to have a test average of no less than 80?
g less-than-or-equal-to 16
g greater-than-or-equal-to 16
g less-than-or-equal-to 64
g greater-than-or-equal-to 64

Answer 1

Answer:

x ≥ 64

Step-by-step explanation:

We want to find the average

Let x be the 5th grade

We want it to be no less than 80

Add up the scores and divide by 5

( 80+ 72+ 96+ 88+x)/5 ≥ 80

Combine like terms

( 336+x) /5 ≥ 80

Multiply each side by 5

336+x ≥ 400

Subtract 336 from each side

x ≥ 400-336

x ≥ 64