Is this word problem solvable?

[Hoi Polloi]

[ QUOTE ]
d1 = 2 miles + (v-s)(1 hour) = 2 + v - s

[/ QUOTE ]

Where did the units go here? Canoeist travels upstream 2 miles and encounters log, an hour later he turns around. How does the distance before the log correlate to the time after the log? Unless we read "after *another* hour" to mean that the first 2 miles took an hour, I don't see how this is solvable.