so she has 300 bucks, and the costs are 127 + 75, 202, plus the show entrance fee of 20 bucks per head.
so for 1 person is 20(1), for 2 is 20(2) bucks, for 3 is 20(3) and for "x" persons is 20(x) or 20x.

so, she can only pay for 4 whole persons, now including herself that'd be her and 3 cousins then.