Brain Help Keep getting negative numbers

Question

A movie theater has a seating capacity of 285. The theater charges $5.00 for children, $7.00 for students, and $12.00 of adults. There are half as many adults as there are children. If the total ticket sales was $ 2066, How many children, students, and adults attended?

children attended.

students attended.

adults attended.

Answer 1

5c +7s + 12a = 2066

a =c/2

c + s +a = 285

s = 285-c -c/2

5c +7(285-c-c/2) +12(c/2) = 2066

5c -7c -7c/2 + 6c = 2066-7(285) = 2066-1995= 71

c/2= 71

c= 2(71) = 142 children

a= 142/2 = 71 adults

s = 285-71-142 = 285-213 = 72 students

5(142) + 7(72) + 12(71)

= 710 +504 + 852

= 2066