In dry air at 68 ° F (20 ° C), the speed of sound is, or a kilometre in or a mile in.
The speed of sound is. This is in dry air at 68 ° F (20 ° C). The speed of sound a kilometre in. This is in dry air at 68 ° F (20 ° C). The speed of sound a mile in. This is in dry air at 68 ° F (20 ° C).