Question 125702
the land part of the trip is the same, coming or going, so concentrate on the water


distance equals rate times time __ it takes an hour longer to go upstream


let t="return time on water" __ (20-4)(t+1)=(20+4)(t) __ 16t+16=24t __ 16=8t __ t=.5


so 12 mi [24(.5)] on water and 180 mi [60(3.5-.5)] on land