SOLUTION: Joe has scores of 94, 71, 89, 73 on his first four exams in his math class. He wants to get a final grade of B for the course. To do this, his exam average must be greater than o
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Question 519932: Joe has scores of 94, 71, 89, 73 on his first four exams in his math class. He wants to get a final grade of B for the course. To do this, his exam average must be greater than or equal to 80 and less than 90. he has one exam remaining. What range of scores will give him a final grade of B
Show the answer mathematically.
Write the answer as a statement. Answer by Maths68(1474) (Show Source):
You can put this solution on YOUR website! Let
Socre of fifth exam = x
Avarage for five exams = (97+71+89+73+x)/5 = (324+x)/5
His exam average must be greater than or equal to 80 and less than 90
80≤(324+x)/5<90
Now
For 80≤(324+x)/5
80≤(324+x)/5
Multiply by 5
5*80≤5*(324+x)/5
400≤(324+x)
400-324≤x
76≤x
For
(324+x)/5<90
Multiply by 5
5*(324+x)/5<90*5
324+x<450
x<450-324
x<126
Range of x
76≤x<126
Range of marks is between 76 and 125
He must score marks between 76 and 125 in his fifth test to maintain an average which will give him a grade B.
If the total marks of an exam is 100 then range must be between 76 and 100.
