Atrain has 100 passenger seats. tickets for the train cost $200 per passenger when every seat is sold. when there are unsold seats, each passenger must pay an additional $5 per unsold seat. if x represents the number of unsold seats on the train, which of the following expressions represents the total number of dollars collected from passengers on the train?
a) 300-5x^2
b) (200+x)(100-5x)
c) (200-x)(100+5x)
d) (200+5x)(100-x)