Question

(20 points)

Josephine is taking a college course, and her professor bases the course grade on the average of 2 tests taken in the semester. She wants to know what she needs to earn on the last test to maintain her grade. Rearrange the following equation for b, where A is the average of 2 test scores, a and b.

A = a + b over 2


b = 2A + a

b = 2A − a

b = 2A(a)

Answer 1

A = a + b over 2

First multiply both sides by 2:

2A = a+b

Now subtract a from both sides:

b = 2A - a