Help me solve this please!
Movie Tickets
Tickets to a 3D movie cost $13 for an adult and $10 for each child. A total of $859 was collected in ticket sales for the 7:15PM show.

Write a linear equation in general form to represent this situation. Let C represent the number of children's tickets and A represent the number of adult tickets sold.
Equation:
If 53 adult tickets were sold, how many children were there?
There were children at the movie.