Bob made honor roll with all A’s and B’s. He has 7 classes and his parents give him $2 for each A and $1 for each B. If Bob earned $11, how many A’s and how many B’s did he earn?

Answer 1

Hi Taylor,

Here we'll want to use a system of equations to solve this problem. Let a be the number of A's Bob earned and let b be the number of B's he earned. We know that he took 7 total classes, so the number of a's plus the number of b's has to equal 7. We also know that he earned $2 for each a and $1 for each b. He earned $11 total, so $2 times the number of a's plus $1 times the number of b's will equal 11.

Therefore the system of equations is:

a+b=7

2a+1b=11

Now solve for a and b.

b = 7 - a

2a+ 1(7-a) = 11

2a +7 - a = 11

a = 4

b = 7 - a

b = 7 - 4 = 3

Bob earned 4 a's and 3 b's.