systems of equations

Question

You are selling tickets for a high school play. Student tickets cost $4 and general admission tickets cost $6. You sell 31 tickets and collect $170. Write the system of equations that could be used to determine the number of student tickets, s, and the number of general admission tickets, g, were sold for the high school play. How many student tickets did you sell? 

Answer 1

4S+6G = 170

S+G =31

4S+4G = 124 subtract from 1st equation to eliminate one variable

2G = 46

G= 23 tickets

S = 31-23 = 8 student tickets

8$4 + 23$6 = $32 + $138 = $170 total