9. An experiment uses microphone moving toward a speaker as away to measure the speed of sound in different media. In air, thefrequency heard by the moving microphone is 20% higher than thefrequency of the sound when the microphone is at rest. When the gasin the experimental system is replaced by helium, the frequencyheard by the moving microphone is now only 6.8% higher than whenthe microphone is at rest. Based on this information, what is thespeed of sound in helium?
