Slow day, eh?
You guys are to much.
c=3.0X10^8 meters/second (if I remember correctly)
aprox 186,000 miles/second
Sound varies, proportional to the density of the media. (=0 in space...
that's why "in space, nobody can hear you scream.")
aprox. 750 miles/hour in "dry" air at sea level.
FWIW