You can
put this solution on YOUR website!28 days an orbit, i would guess for the time --> 28x24x3600 = 2419200 seconds
From the web, the moon's orbit is 480000miles in diameter, so the circumference of the orbit =

-->
As speed = distance travelled/time taken
so speed =
speed = 0.6miles/second which is 2160miles/hour.
Jon