Every attendee at a monster truck rally paid the same direct

Every attendee at a monster truck rally paid the same admission fee. How many people attended the rally?

(1) If the admission feehad been raised to $20 and twice as many people had attended, the total admission fees collected would have been three times greater.

(2) If the admissionfee had been raised to $30 and two-thirds as many people had attended, the total admission fees collected would have been 150% of the actual admission fees collected.
...

---