# motion problem

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Ric can row upstream against a current at 6kph in 10 hrs while it will take him only 4 hrs going back. how far does he go upstream?

(w/ solution pls... tnx)

• motion problem -

rate of paddling in still water ---- x km/h
speed of the river -------------- y km/h
x-y = 6
x = y+6

distance uprstream = 6(10) = 60 km
distance downstream = 4(x+y) = 4(y+6 + y)
= 8y + 24

8y + 24 = 60
y = 4.5
x = 10.5

Actually I did a lot of extra work.
The question was , how far does he go upstream

all I needed was 10(6) = 60 km

btw, in metric we say km/h not kph

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