Compare the motion of two birds. Which bird was moving at a lower speed?

 - a bird that moved 15kilometers in 10hours
 - a bird that moved 90kilometers in 10hours
Look at the distance each bird moved and the time it took to move that distance.
One bird moved 15 kilometers in 10 hours.
The other bird moved 90 kilometers in 10 hours.
Notice that each bird spent the same amount of time moving. The bird that moved 15 kilometers moved a shorter distance in that time. So, that bird must have moved at a lower speed.