Tickets to Jimmy Johns field cost a total of $264 for the family reunion. Tickets cost $10 for adults and $6 for children. There are twice as many...

Tickets to Jimmy Johns field cost a total of $264 for the family reunion. Tickets cost $10 for adults and $6 for children. There are twice as many children as adults. What is a system of equation that can be used to find "a", the number of adult tickets sold, and "c", the number of children tickets sold. Then solve the system to find how many adult and children tickets were purchased.