Question 1015548
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The sum of grades to average 77 is 462. (6 x 77).
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The sum of grades to average 85 is 510 (6 x 85).
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{{{462 < 79+85+75+66+79+x <=510}}}
{{{462 < 384+x <= 510}}} Subtract 384 all the way through.
{{{78 < x <= 126}}}
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Since he cannot score high enough to average more than 85,
his possible scores are greater than 78. (to 100)