Aboat traveled 280 miles downstream and back. the trip downstream took 7 hours. the trip bck took 14 hours. find the speed of the boat in still water and the speed of the current.

Recall your d = rt, distance = rate * time

bearing in mind that the trip over, upstream, is the same distance as back, 280 miles.

if say, the boat has a speed rate of say "b", and the current has a speed rate of "c", so, when the boat was going upstream, it really wasn't going "b" fast, it was going "b-c" fast, because the stream is subtracting speed from it, because is going against the stream.

And when the boat was going downstream, is not going "b" fast either, is going "b+c" because, since it's going with the current, the current's rate is adding speed to it.



what's the speed of the boat?  well, 40 - c = b.

The correct graph is the second one, with the points being at (-6,0), (2,0) and reaching down to (-2,-8)