Question 1175104
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I'll let you do the work....<br>
(1) The best grade he can get is if he gets 100% on the final.  It counts 15% of the total grade; his current average counts for 85% of his grade.  His best possible final grade is<br>
{{{(.85(81)+.15(100))/100}}}<br>
(2) Let x be the minimum grade he can get on the final.  Then his final grade is 85% of his current average of 81, plus 15% of x.  You want that average to be 75%:<br>
{{{(.85(81)+.15(x))/100 = .75}}}<br>
The first problem only involves performing a calculation; the second requires solving an equation using basic algebra....<br>