Compare the motion of three ships. Which ship was moving at the lowest speed?

 - a ship that moved 230miles east in 10hours
 - a ship that moved 220miles south in 10hours
 - a ship that moved 240miles west in 10hours
Look at the distance each ship moved and the time it took to move that distance. The direction each ship moved does not affect its speed.
Notice that each ship moved for 10 hours. The ship that moved 220 miles moved the shortest distance in that time. So, that ship must have moved at the lowest speed.