Arturo O. answered • 08/16/17

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speed of boat in still water = 40 mph

w = speed of stream

upstream time is 33 min = 33/60 hrs = 11/20 hrs

downstream time is 22 min = 22/60 hrs = 11/30 hours

The distance (d = vt) traveled either way is the same, but at different speeds and times.

Set upstream and downstream distances (vt) equal and solve for w.

(40 - w)(11/20) = (40 + w)(11/30)

(40 - w)/20 = (40 + w)/30

3(40 - w) = 2(40 + w)

120 - 3w = 80 + 2w

40 = 5w

**w = 40/5 mph = 8 mph**

Test the solution.