<PRE><B>Question 531788</B>
the river boat delta duchess paddled upstream at 12 km/h, stopped for 2 hours of sight seeing, and paddled back at 18 km/h.
 how far upstream did the boat travel if the total time for the trip, including the stop, was 7 hours
:
We only care about the traveling time which is 5 hrs
:
Let d = one way distance
:
Write a time equation: time = dist/speed
:
up time + down time = 5 hrs
{{{d/12}}} + {{{d/18}}} = 5
Multiply by 36 to get rid of the denominators, results:
3d + 2d = 36(5)
5d = 180
d = 180/5
d = 36 miles upstream
:
:
Check this by finding the actual time each way
36/12 = 3 hrs
36/18 = 2 hrs
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totals: 5 hrs</PRE>