Devin is training for a competitive race by swimming and running. He covers a total distance of 9 km by swimming for 45 minutes and running for 20 minutes. The following day he swims for 30 minutes and runs for 40 minutes, covering a total of 14 km. Which system of linear equations can be used to find Devin's swimming rate (x) and his running rate (y) in kilometers per hour? A) 3 4 x + 1 3 r = 9 1 2 x + 2 3 y = 14 B) 3 4 x + 1 3 y = 14 1 2 x + 2 3 y = 9 C) 3 4 x + 1 3 y = 9 1 2 x − 2 3 y = 14 D) 3 4 x + 1 3 y = 23 1 2 x + 2 3 y = 23