SOLUTION: Sean has taken three exams and earned scores of 77, 72, and 85 out of a possible 100 points. He needs an average of at least 80 to earn a B in the class. What range of scores on th

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Sean has taken three exams and earned scores of 77, 72, and 85 out of a possible 100 points. He needs an average of at least 80 to earn a B in the class. What range of scores on th      Log On


   

Question 344841: Sean has taken three exams and earned scores of 77, 72, and 85 out of a possible 100 points. He needs an average of at least 80 to earn a B in the class. What range of scores on the fourth (and last) 100 point test will guarantee a B in the class.
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
(77+72+85+x)/4=80
(234+x)/4=80
234+x=4*80
234x=320
x=320-234
x=86 is the lowest score for a B.
(77+72+85+100)/4=x
334/4=x
334=4x
334/4=x
83.5=x
The max score of 100 gives an average of 83.5.
Range is 86 to 100.