Sound waves are mechanical waves, which means they require a medium to travel through. The speed of sound depends on the properties of the medium, such as its density and elasticity.

In general, sound travels faster in denser media. This is because the particles in a denser medium are closer together, so they can transmit the sound waves more quickly. For example, sound travels faster in water than in air, and faster in steel than in water.

The elasticity of a medium also affects the speed of sound. Elasticity is the ability of a material to return to its original shape after being deformed. The more elastic a material is, the faster sound waves can travel through it. For example, sound travels faster in a stretched rubber band than in a relaxed rubber band.

In addition to density and elasticity, the temperature of a medium can also affect the speed of sound. Sound waves travel faster in warmer media. This is because the particles in a warmer medium are moving faster, so they can transmit the sound waves more quickly. For example, sound travels faster in warm air than in cold air.

So, to answer your question, sound travels faster in a solid than gas or water because solids are denser and more elastic than gases or water.