SOLUTION: Luke received grades of 88%, 72% and 82% on the three tests during the semester in a business course. If the final exam counts as two tests, what possible scores on the final exam

Algebra ->  Average -> SOLUTION: Luke received grades of 88%, 72% and 82% on the three tests during the semester in a business course. If the final exam counts as two tests, what possible scores on the final exam       Log On


   

Question 1135261: Luke received grades of 88%, 72% and 82% on the three tests during the semester in a business course. If the final exam counts as two tests, what possible scores on the final exam will give him a final average of at least 80%?
Found 2 solutions by ikleyn, rothauserc:
Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.
%2888+%2B+72+%2B+82+%2B+2x%29%2F%283%2B2%29 >= 80.      <<<---=== It is how I understand/interpret the condition.


Or, equivalently,


%2888+%2B+72+%2B+82%2B+2x%29%2F5 >= 80


88 + 72 + 82 + 2x >= 400


2x >= 400 - 88 - 72 - 82 = 158


x >= 158%2F2 = 79.


Answer.  Score under the question is >= 79.


Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
(88 +72 +82 +2x)/5 = 80
:
multiply both sides of = by 5 and simplify
:
242 +2x = 400
:
2x = 158
:
x = 79
:
***************************************************************************
final exam score of 79 or greater will give a final average of at least 80%
***************************************************************************
: