Jane has scores of 84, 92, and 89 on her first 3 exams. What does she need to score on the next exam so that her overall average will be 90?

Feb 26, 2015

For the average of 4 exams to be 90
the total of all 4 exams must be $4 \times 90 = 360$

Let fourth exam score be $x$

$84 + 92 + 89 + x = 360$
$265 + x = 360$
$x = 95$

She will need to score $95$ on her fourth exam to average $90$