Question 131207
To get an average grade of 90 or better (>or= 90), let the grade on the fifth test be x, then find the average of the five test scores.
{{{(84+93+92+89+x)/5 >= 90}}} Add the four scores and multiply both sides by 5.
{{{358+x <= 450}}} Subtract 358 from both sides.
{{{x <= 92}}}
The student has to score at least 92 on the fifth test to get an average grade of 90 on the five tests.