Each person attending a fund-raising party for a certain club was charged the same admission fee. How many people attended the party?
a) If the admission fee had been $0.75 less and 100 more people had attended, the club would have received the same amount in admission fees.
b) If the admission fee had been $1.50 more and 100 fewer people had attended, the club would have received the same amount in admission fees.

I thought each would be sufficient assuming X is attendees while $1.00 is sample fee. Should I be equating the 2?