Solve the system by the addition method. - 3x + 9y = -4 24x - 72y = 33 Select the correct choice below and, if necessary, fill in the answer box within your choice. O A. The solution is (Type an ordered pair.) O B. There are infinitely many solutions. O C. There is no solution.An airplane has a total of 254 seats. The number of coach-class seats is 50 more than 2 times the number of first-class seats. How ma of each type of seat are there on the plane? There are coach-class seats on the plane.A riverboat travels 75 km downstream in 3 hours. It travels 68 km upstream in 4 hours. Find the speed of the boat and the speed of the stream. The speed of the boat is and the speed of the stream is