SOLUTION: Don Williams uses his small motorboat to go 4 miles upstream to his favorite fishing spot. Against the current, the trip takes 2/5 hours. With the current the trip takes 1/5. How f

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Question 720815: Don Williams uses his small motorboat to go 4 miles upstream to his favorite fishing spot. Against the current, the trip takes 2/5 hours. With the current the trip takes 1/5. How fast can the boat travel in still water. What is the speed of the current?? thanks.
Found 2 solutions by Alan3354, stanbon:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Don Williams uses his small motorboat to go 4 miles upstream to his favorite fishing spot. Against the current, the trip takes 2/5 hours. With the current the trip takes 1/5. How fast can the boat travel in still water. What is the speed of the current??
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1 ? is sufficient.
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Find the speed upstream and downstream using d = r*t.
How fast can the boat travel in still water. (A ? would be good there.)
It's the average of the speed upstream and downstream.
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The speed of the current (called the current) is the difference between the waterspeed and the groundspeed.
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This problem has been posted and solved 1000's of times on this site. Look it up.

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Don Williams uses his small motorboat to go 4 miles upstream to his favorite fishing spot. Against the current, the trip takes 2/5 hours. With the current the trip takes 1/5. How fast can the boat travel in still water. What is the speed of the current??
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Upstream DATA:
distance = 4 miles ; time = 2/5 hr. ; rate = d/t = 4/(2/5) = 10 mph
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Downstream DATA:
distance = 4 miles ; time = 1/5 hr ; rate = d/t = 4/(1/5) = 20 mph
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Equation:
b + c = 20 mph
b - c = 10 mph
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2b = 30
b = 15 mph (speed of the boat in still water)
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b + c = 20 mph
15 + c = 20
c = 5 mph (speed of the current)
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cheers,
Stan H.
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