a van which holds 10 people. It will cost $25 for parking and tickets to enter the park are $18 per person.

Hiya, I'm assuming you need to work out how much will be paid altogether?

If so:

25 + 10 (18)

= 25 + 180

= $205

Or you may need to work out how much each person would pay, in which case:

18 + 25/10

= 18 + 2.5

= $20.50