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

 - a ship that moved 215miles north in 10hours
 - a ship that moved 355miles east in 10hours
 - a ship that moved 365miles north 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 365 miles moved the farthest distance in that time. So, that ship must have moved at the highest speed.