Question

Adult tickets to the fall play cost $8 and student tickets cost $4. The drama class sold 30 more adult tickets than student tickets to the fall play. If the class collected $840 from ticket sales, how many adult tickets were sold?

Answer 1

A=s+30
8a+4s=840
8(s+30)+4s=840
12s+240=840
12s=600
s=50
a=50+30=80

Check:
80(8)+50(4)=640+200=840 CHECKS. 

80 Adults and 50 Students.