substitution
posted by Artie .
Tickets to a movie cost $7.25 for adults and $5.50 for students. A group of friends purchased 8 tickets for $52.75.
Write a system of equations to represent the situation.
How many adult tickets and student tickets were purchased?

A + C = 8
7.25 A + 5.5 C = 52.75
Solve for A (# of adult tickets) and C (# of children's tickets) 
let the number of adult tickets be x
then the number of student tickets will be 8x
7.25x + 5.5(8x) = 52.75
etc 
Thank you. I'm really having problems with math.

i need help with substitution