The speed of sound is the distance travelled per unit time by asound wave as it propagates through a medium.
However, the speed of sound varies from substance to substance: sound travels most slowly in gases; it travels faster in liquids; and faster still in solids.
So the factors which determines the speed of sound are;
1)The medium in which it travels.
2)The freequency of sound(or it's wavelength)
Hope it clears,Good luck.