What is the answer and how did you find that?

Answer:
a) $15287.71
b) $15017.64
c) $16,368 − r%
Step-by-step explanation:
Mary's car price (including tax): $16,368
[possible tax rates and listing prices]
a) 6.6%
➠ $15287.71
b) 8.25%
➠ $15017.64
c) r (any rate)
➠ $16,368 − r%
How did I find my answers?
I had to find the sales tax, and subtract it from the overall cost of the item.