SOLUTION: An arithmetic student needs an average of 70 or more to receive credit for the course. She scored 82, 64, and 98 on the first three exams. Write an inequality representing the sc

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Question 51013: An arithmetic student needs an average of 70 or more to receive credit for the course. She scored 82, 64, and 98 on the first three exams. Write an inequality representing the score she must get on the last test to receive credit for the course
Answer by junior403(76) (Show Source):
You can put this solution on YOUR website!
In a problem such as this we can figure it out much like we would figure out a student's average grade for a series of tests. We add all the scores together and divide by the number of scores. Only, in this case there is one unknown in that series of tests, lets call that x.
82 + 64 + 98 + x
These are the four scores that we have, correct?
Now we simply add these together and divide by the number of scores, 4.
And we want that result to be greater than or equal to the minimum grade she must get in order to recieve credit, 70.

now, to make it easier to work with, we can multiply the entire equation by 4 to cancel out the denominator, remember to multiply both sides of the equation...

the 4's cancel and we can multiply the 70 by 4...

then we perform the indicated operations.

subtract 244 from both sides...

So 36 is the minimum grade the student can get on the test to average a 70.
I hope this helps.
good luck!