An object travels from a point X to another point Y in 10 s. The distance between them is 30 m. It travels again from Y to Z and covers 40 m. The average speed of the object during the whole journey is 2 m/s. How long the object takes to travel from Y to Z?​

Ibelieve the answer is arteries

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.