the trampoline park charges $100 for 8 people. the cost includes a $9 jumping fee per person plus the cost of a large pizza for the group. how much do 2 pizzas cost
The cost for 8 people would be $9 x 8 = $<<9*8=72>>72.
Thus, the cost of the 2 pizzas is $100 - $72 = $<<100-72=28>>28. Answer: \boxed{28}.