Q. The sound travels through the left tube LXM, which has a fixed length. Concurrently, the sound travels through the right tube LYM, length of which can be changed by moving the sliding section. At M, sound waves coming from the two paths interfere. As the length of the path LYM is changed, sound loudness detected by the microphone changes. When the sliding section is pulled out by 0.020 m the loudness changes from a greatest to a minimum. Find out the speed at which sound travels through the gas in the tube.