Question

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 C is the average of 2 test scores, a and b.

C equals the quantity a plus b all over two

b equals two times C over a
b = 2C + a
b = 2C − a
b = 2C(a)

Answer 1

C = (a+b)/2

to isolate b:

1. multiply both sides by 2
2. subtract a from both sides

Answer 2

Thanks for helping!