SOLUTION: I not sure how to write the equation for this one the one i did was wrong. To get to his parents' house, John must travel at a speed of 60 mph on land and then use a motorboat t

Question 125702: I not sure how to write the equation for this one the one i did was wrong.
To get to his parents' house, John must travel at a speed of 60 mph on land and then use a motorboat that travels at a speed of 20 mph in still water. John goes by land to a dock and then travels on a river against a current of 4 mph. He reaches his parent's home in 4.5 hours. The return trip takes him 3.5 hours. How far do his parents live from his house?

Answer by scott8148(6628) (Show Source): You can put this solution on YOUR website!
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
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