This problem is solved using dimensional analysis. It is known that there are 5280 yards in a league and that there are 3 feet in one yard. Finally, it is known that there are 6076 feet in one nautical mile. As a result, we can multiply these dimension together, making certain that the units cancel and leave us with only nautical miles.
It is done as follows:
(610 leagues)(5280yds/1 league)(3 ft/1yd)(1 nautical mile/6076ft)= 1590 naurtical miles.
