Joe drove at the speed of 45 miles per hour for a certain distance. he then drove at the speed of 55 miles per hour for the same distance. what is the average speed for the whole trip?

Jet streams are relatively narrow bands of strong wind in the upper levels of the atmosphere. the winds blow from west to east in jet streams but the flow often shifts to the north and south. jet streams follow the boundaries between hot and cold air. the earth's rotation is responsible for the jet stream as well.