SOLUTION: A cruise boat travels 84miles down stream in 4 hours and returns to its starting point upstream in 7 hours. Write a system of equation to find the speed of the boat and the speed

Question 753996: A cruise boat travels 84miles down stream in 4 hours and returns to its starting point upstream in 7 hours. Write a system of equation to find the speed of the boat and the speed of the current ehere b represents the speed of the boat and c represents the sepeed of the current.
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
A cruise boat travels 84miles down stream in 4 hours and returns to its starting point upstream in 7 hours. Write a system of equation to find the speed of the boat and the speed of the current ehere b represents the speed of the boat and c represents the sepeed of the current.
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Speed d/stream = 84/4 = 21 mi/hr
Speed u/stream = 84/7 = 12 mi/hr
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The boat's speed is the average of the 2, = (21+12)/2 = 16.5 mi/hr
b = 16.5 mi/hr
The current is the difference = 21 - 16.5 = 4.5 mi/hr
c = 4.5 mi/hr
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I don't know how to make it complicated, nor do I see any reason to do so.

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