Calculating Adult Tickets Sold at Theater

At a local theater, the price of an adult ticket is $12, and the price of a child ticket is $8. On a certain day, the theater sold a total of 150 tickets, collecting $1440 in revenue. Determine the number of adult tickets sold. Let the number of adult tickets be represented by the variable $a$ and the number of child tickets be represented by the variable $c$.

Formulate a system of equations based on the information provided and solve for $a$.