Question is Incomplete, Complete question is given below.
One evening 1500 concert tickets were sold for the Jazz Fest. Tickets cost $25 for covered pavilion seats and $15 for lawn seat. Total receipts were $28,500. How many of each type of ticket were sold?
Answer:
Number of Pavilion seat is 600 and number of lawn seats is 900.
Explanation:
Given:
Total Number of ticket sold = 1500
Let number of Pavilion seat be x.
Let number of lawn seats be y.
hence the equation can be framed as;

Also Given
Total Amount made = $28,500
Cost of pavilion seat = $25
Cost of lawn seat = $15
Total Amount made is equal to Cost of pavilion seat multiplied by number of Pavilion seat plus Cost of lawn seat multiplied by number of lawn seats.

Dividing by 5 on both side we get;

Now Multiplying equation by 3 we get;

Now Subtracting equation 3 from 2 we get;

Substituting the value of x in equation 1 we get;

Hence Number of Pavilion seat is 600 and number of lawn seats is 900.