In which type of muffler crest of one wave coincide with the trough of the second wave?

In which type of muffler crest of one wave coincide with the trough of the second wave? Correct Answer Wave cancellation type

In wave cancellation type, the length of these paths is so adjusted that after they come out of the muffler, the crest of one wave coincides with the trough of the second wave, thus reducing noise.

Related Questions

Which one of the following term is used for the distance between trough to crest of a wave?
What is the distance between a crest and a consecutive trough in a transverse wave?