Compare the motion of two speed walkers. Which speed walker was moving at a lower speed?

 - a speed walker who moved 70kilometers in 10hours
 - a speed walker who moved 75kilometers in 10hours
Look at the distance each speed walker moved and the time it took to move that distance.
One speed walker moved 70 kilometers in 10 hours.
The other speed walker moved 75 kilometers in 10 hours.
Notice that each speed walker spent the same amount of time moving. The speed walker who moved 70 kilometers moved a shorter distance in that time. So, that speed walker must have moved at a lower speed.