Question

Last semester, Zachary earned an average score of 80 points on math tests. So far this semester, his average score is 15% lower. What is the average of Zachary's scores this semester?

Answer 1

The answer would be 12

Explanation:

15/100 = X/80

To solve the equation above for X, you first switch the sides to get the X on the left side, then you multiply each side by 80, and then finally divide the numerator by the denominator on the right side to get the answer.

The equation

15/100 = X/80

X/80 = 15/100

X*80/80 = 15*80/100

X = 1200/100

X = 12