Answer:
A = 2, the number is 3221
Step-by-step explanation:
In order for the number to be divisible by 9, the sum of it's digit has to be divisible by 9.
In our case,
where k is an integer. the easiest way happens when k=1

Higher values of k will likely most work (with k=2 you get A to be a non-integer, which can't work since it's the digit of a number, and with higher values of K you're not getting a number in base 10.
I'm not too sure either.
5(5) + 3(5) = 40 and
5(2) + 3 (10) = 40
If you can't think of anything maybe that'll help
They use percents less than one to get the the exact number
Answer:
it should be 17.9, I don't really know how to explain it I'm sorry-
Answer:
I want to say its C - 8.12 units. But I think it could also be D- 8.25 units. Just not 100% sure.