Product property is the answer
I think they should keep it around, even if it might not be the most efficient strategy. After all, what if you need to solve a problem using multiple strategies?
The number 8 is a multiple of 16, 2 x 8 = 16 . And the number 8 + 10 = 18
So, I would think it's 8.
Hope I was able to help you. :-)
Diagonals bisect each other



Option B
The final balance is $9,845.36.
The total compound interest is $845.36.
If this is wrong, I do apologize.