I graphed it out and it seems that both A and C are correct. I would check them to make sure.
Answer:

Step-by-step explanation:
9514 1404 393
Answer:
p = -9 5/9
Step-by-step explanation:
Undo what is done to p.
Multiply by 2.
p +10 = 4/9
Subtract 10.
p = 4/9 -10
p = -9 5/9
Yes because 18% is an abbysmal amount for a tip