Compare the motion of two ducks. Which duck was moving at a lower speed?

 - a duck that moved 315miles in 5hours
 - a duck that moved 285miles in 5hours
Look at the distance each duck moved and the time it took to move that distance.
One duck moved 285 miles in 5 hours.
The other duck moved 315 miles in 5 hours.
Notice that each duck spent the same amount of time moving. The duck that moved 285 miles moved a shorter distance in that time. So, that duck must have moved at a lower speed.