The average price of a ticket to a baseball game can be approximated by

p(x)=0.03x2+0.51x+9.85, where x is the number of years after 1991 and p(x) is in dollars.

a) Find p(3).

b) Find p(13).

c) Find p(13)p(3).

d) Find p(13)p(3)133,

and interpret this result.