SOLUTION: Correct Question: Two campers left the camp at 8:00 AM to paddle their canoe 10 km upstream to a fishing cove. They fished for 3.5 hours then paddle back to the campsite and arri
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Question 918878: Correct Question: Two campers left the camp at 8:00 AM to paddle their canoe 10 km upstream to a fishing cove. They fished for 3.5 hours then paddle back to the campsite and arrived at 6:00 PM. If the rate of the current was 3 km/h, how fast could the campers paddle in still water? Answer by lwsshak3(11628) (Show Source):
You can put this solution on YOUR website! Correct Question: Two campers left the camp at 8:00 AM to paddle their canoe 10 km upstream to a fishing cove. They fished for 3.5 hours then paddle back to the campsite and arrived at 6:00 PM. If the rate of the current was 3 km/h, how fast could the campers paddle in still water?
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let x=speed campers can paddle in still water
x+3=speed campers can paddle downstream
x-3=speed campers can paddle upstream
distance/speed=travel time
..
10/(x-3)+3.5+10/(x+3)=10(8 AM to 6 PM)
10/(x-3)+10/(x+3)=6.5
lcd:(x+3)(x-3)
10(x+3)+10(x-3)=6.5(x^2-9)
10x+30+10x-30=6.5x^2-58.5
20x=6.5x^2-58.5
6.5x^2-20x-58.5
solve for x by quadratic formula:
a=6.5, b=-20, c=-58.5
ans:
x=4.9
speed campers can paddle in still water=4.9 km/hr
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