Question 1207382
Going into the final exam,which will count as two-thirds of the final grade, 
Mike has test scores of 86,80,84,and 90.What score does Mike need on the final
in order to earn a B,which requires an average score of 80? What does he need to
earn an A,which requires an average of 90? 
<pre>
For the final exam to count 2/3, to figure his score for the course, Mike must
add his final exam grade 2 times and his test average only 1 time and divide by
3.

Let his required final exam grade be x

His test average is

{{{86+80+84+90)/4}}}{{{""=""}}}{{{340/4}}}{{{""=""}}}{{{85}}}

His score for the course = {{{(x+x+85)/3}}}{{{""=""}}}{{{(85+2x)/3}}}

{{{(85+2x)/3}}}{{{""=""}}}{{{80}}} to get a B
{{{85+2x}}}{{{""=""}}}{{{240}}}
{{{2x}}}{{{""=""}}}{{{155}}}
{{{x}}}{{{""=""}}}{{{77.5}}}

{{{(85+2x)/3}}}{{{""=""}}}{{{90}}} to get an A
{{{85+2x}}}{{{""=""}}}{{{270}}}
{{{2x}}}{{{""=""}}}{{{185}}}
{{{x}}}{{{""=""}}}{{{92.5}}}
  
Edwin</pre>