Two docks are on the same river, separated by $4\mathrm{.}8$ km $.$ The river current is flowing at $6\mathrm{.}8k\frac{m}{h}r.$ You have a small boat that can travel at a speed of $10\mathrm{.}2k\frac{m}{h}r$ relative to the water.

Starting at the first dock, you travel $4\mathrm{.}8$ km downstream to the second dock and then immediately turn around and travel $4\mathrm{.}8$ km upstream back to the first dock. How long does this round trip take?