Charles owed $390 to his friend. on the first day charles paid his friend $12. each following week the amount charles paid his friend increased by the same amount. after 10 payments, charles had paid back the full amount. by how much did each payment increase?

Mason and christian go to the movie theater and purchase refreshments for their friends. mason spends a total of $45.75 on 3 bags of popcorn and 6 drinks. christian spends a total of $71.50 on 6 bags of popcorn and 4 drinks. write a system of equations that can be used to find the price of one bag of popcorn and the price of one drink. using these equations, determine and state the price of a drink, to the nearest cent.