Question 792087
His average grade on tests are 68%,78%,90&, and 91%.
 What score should he score to have an average of at least 85%?
:
Let x = grade on the 5th test to have at least 85
{{{(68+78+90+91+x)/5}}} => 85
:
{{{(327+x)/5}}} => 85
Multiply both sides by 5
327 + x => 425
subtract 327 from both sides
x => 425 - 327
x => 98
:
He needs to get a 98 or greater to get at least an 85 average