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 A is the average of 2 test scores, a and b.
A equals the quantity a plus b all over two

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

Answer 1

b = 2A - a

a + b = 2A

(a + b)/2 = A

Answer 2

Answer:

The equation for  b is given by:

              $b=2A-a$

Step-by-step explanation:

It is given that:

A denotes the average score of the two test taken in the semester.

The two test that are taken have a score as a and b.

Now the average score A in terms of a and b is given by:

$A=\dfrac{a+b}{2}$

Now, on solving for b from this equation:

Firstly we multiply both side by 2.

i.e. we have:

$a+b=2A$

Now on subtracting both side by a we have:

$b=2A-a$