The speed of sound in "medium air" is a bit ambiguous, as it depends on the specific temperature and humidity of the air.

However, a general approximation for the speed of sound in dry air at 20°C (68°F) is:

343 meters per second (m/s)

or

767 miles per hour (mph)

or

1,235 kilometers per hour (km/h)

Here's why it varies:

* Temperature: Sound travels faster in warmer air because the molecules are moving faster and collide more frequently.

* Humidity: Humidity makes the air denser, which slightly slows down the speed of sound.

To get a more precise measurement, you'd need to know the exact temperature and humidity of the air.