19. A family of two adults and five kids pay $61 for tickets in a movie theater. A family of three adults and two kids pay $53. Find the prices for an adult ticket and for a kid ticket. (Solve the problem by composing a linear system)

20. It takes three hours for a plane to fly 2,400 mi from A to B with a tailwind and 3 hours 20 mins from B to A against the wind. Find the speed of the plane and the speed of the wind, assuming that the notion is uniform. (Solve the system by composing a system of linear equations?