A microphone is moving in air toward a stationary source of sound (speed of sound = 343m/s). The detected frequency is 82.7Hz greater than the emitted frequency. When the microphone moves at the same speed toward the same stationary source in a liquid, the detected frequency is only 21.6Hz greater than the emitted frequency. What is the speed of sound in the liquid? I really need help! I can't figure out this problem and I've gone all through my textbook and lecture notes!