SOLUTION: Simon scored 94, 82, and 97 on his first three tests in Algerbra 2. What grade must he make on the fourth test to keep an average of 90 or greater? I can get the answer by jus

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Question 986450: Simon scored 94, 82, and 97 on his first three tests in Algerbra 2. What grade must he make on the fourth test to keep an average of 90 or greater?

I can get the answer by just trying random numbers but I dont know how to do it correctly.
Found 3 solutions by jim_thompson5910, josgarithmetic, stanbon:
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website!
Let x = score on fourth test

Add up the four test scores and divide by 4 to get the average. We want the average to be 90 or larger, so

So Simon must make an 87 or better to ensure his average is 90 or better.

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Answer by josgarithmetic(39625)   (Show Source):
You can put this solution on YOUR website!
What is the average of the three given scores?
Three of them:

Now you want to consider one more score, so four of them, and you want the average of all four to be 90 or more.

Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website!
Simon scored 94, 82, and 97 on his first three tests in Algebra 2. What grade must he make on the fourth test to keep an average of 90 or greater?
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Let the 4th score be "x".
Solve for "x"::
(94+82+97+x)/4 >= 90
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273 + x >= 360
x >= 87
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Cheers,
Stan H.