Compare the motion of three sailboats. Which sailboat was moving at the highest speed?

 - a sailboat that moved 35kilometers west in 5hours
 - a sailboat that moved 90kilometers west in 5hours
 - a sailboat that moved 55kilometers east in 5hours
Look at the distance each sailboat moved and the time it took to move that distance. The direction each sailboat moved does not affect its speed.
Notice that each sailboat moved for 5 hours. The sailboat that moved 90 kilometers moved the farthest distance in that time. So, that sailboat must have moved at the highest speed.