Question 1024300
You didn't state the mean you want.
Let's call it M.
You want to solve for X, the number of points she needs to score in the 6th game.
So then,
{{{(21+21+24+19+22+X)/6=M}}}
{{{21+21+24+19+22+X=6M}}}
{{{X=6M-21-21-24-19-22}}}
So plug in the value for M and then you'll find X.