What does Emma need to make on her final exam (20%) of her grade to keep her current average (93) to at least a 90 (a-) average
20% of X + 80% of 93 >= 90
.2X + .8(93) >= 90
.2X + 74.4 >= 90
.2X >= 15.6
X >=
X >= 78
She needs to make at least 78.
Edwin