Miner #2 mines 19,687 m (meters ?) of ore in 51 minutes.
That's (19,687/ 51) m (meters ?) per minute.
There are 60 minutes in one hour. So if he maintains that same
average rate for a whole hour, he will mine
(19,687 / 51) x (60) = 23,161 m (meters) of ore.
