Question 378119
Aim for the middle?
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The average is equal to,
{{{A=(78+86+69+79+X)/5}}}
where X is the final grade.
{{{70<A<80}}}
{{{70<(78+86+69+79+X)/5<80}}}
{{{350<(312+X)<400}}}
{{{highlight(38<X<88)}}}