Question

Emerson needs an average of at least 90 points in order to earn an "A" in his science

class. So far, his test scores are 92, 86, and 88. What is the lowest grade Emerson can
score on his final test in order to earn an "A"?
s < 94, Emmerson must earn below a 94 on his final test to earn an "A" in his class.
b) s > 94, Emmerson must earn above a 94 on his final test to earn an "A" in his class.
c) s < 94, Emmerson must earn at most a 94 on his final test to earn an "A" in his class.
d) s 294, Emmerson must earn at least a 94 on his final test to earn an "A" in his class.

Answer 1

D) Emerson must earn at least a 94 on his final test to earn an “A” in his class

Explanation:

We calculate this using mean in this format:

Test Scores / # of Test ≥ 90 (which is an A)

Substitute:

(92 + 86 + 88)+ x / 4 ≥ 90

Add:

266 + x / 4 ≥ 90

Get Rid of the Denominator:

(4) 266 + x / 4 ≥ 90 (4)

Multiply:

266 + x ≥ 360

Isolate x (Subtract 266 From Both Sides):

x ≥ 94

This means that x (His final test score) has to be greater than (above) or equal to 94. A term for greater than or equal to is “at least.” Hope this helps :)