Sound travels

We know that - the sound waves can travel faster and more effectively in liquid medium as compared to air and travel even more effectively in solid medium because solids are packed together tighter than liquids and gases, hence sound can travel fastest in solids. 

The distances in liquids are very shorter than in gases but it is longer than in solids. And similarly the liquids are denser than gases, but it is less dense than solid. Gases are the very slowest because they are the least dense. The molecules in gases are very far apart as compared with solids and liquids.