Answer:
However much he had on his card in the first place.
Step-by-step explanation:
Say he had $500 on his card. He took 0 rides ( no rides ) so he doesn't lose any money. Leaving him with his starting amount, $500.
It's linear and equation of the function is :
f ( x ) = 2x - 1
R(9,0)
S(8,-4)
T(7,4)
V(6,0)