solving systems

Question

An auditorium sold 500 tickets for a play and raised $3400. Let x represent the number of adult tickets sold at $8 each and let y represent the number of student tickets sold at $5 each.  Write and solve a system of equations to determine the number of adult tickets and the number of student tickets that were sold.

Answer 1

8a +5s = 3400

a +s = 500

5a +5s = 2500

subtract last equation from first to get

3a = 900

a = 300 adult tickets

s = 200 student tickets