Compare the motion of two blue whales. Which blue whale was moving at a lower speed?

 - a blue whale that moved 55miles in 5hours
 - a blue whale that moved 50miles in 5hours
Look at the distance each blue whale moved and the time it took to move that distance.
One blue whale moved 50 miles in 5 hours.
The other blue whale moved 55 miles in 5 hours.
Notice that each blue whale spent the same amount of time moving. The blue whale that moved 50 miles moved a shorter distance in that time. So, that blue whale must have moved at a lower speed.