Question 148549
Set up an equation for the average: {{{(84+93+88+x)/4=90}}}


Combine like terms:


{{{(265+x)/4=90}}}


Multiply both sides by 4.


{{{265+x=360}}}


Subtract 265 from both sides


{{{x=95}}}


So for the average grade to be 90, the person would have to get a 95.