SOLUTION: Boat A and boat B leave the same place at the same time at right angles. Boat B travels 7 km per hour slower than Boat A. After 4 hours, they are 68 km apart. Find the speed of ea
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-> SOLUTION: Boat A and boat B leave the same place at the same time at right angles. Boat B travels 7 km per hour slower than Boat A. After 4 hours, they are 68 km apart. Find the speed of ea
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Question 830202: Boat A and boat B leave the same place at the same time at right angles. Boat B travels 7 km per hour slower than Boat A. After 4 hours, they are 68 km apart. Find the speed of each boat Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Boat A and boat B leave the same place at the same time at right angles. Boat B travels 7 km per hour slower than Boat A. After 4 hours, they are 68 km apart. Find the speed of each boat
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Boat A DATA:
time = 4 hrs ; rate = x km/hr ; distance = 4x km
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Boat B DATA:
time = 4 hrs ; rate = x-7 km/hr ; distance = 4x-28 km
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Use Pythagoras::
(4x)^2 + (4x-28)^2 = 68^2
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16x^2 + 16x^2 - 224x + 28^2 = 68^2
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32x^2 - 224x - 3840 = 0
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4x^2 - 28x - 480 = 0
x^2 - 7x - 120 = 0
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(x-15)(x+8) = 0
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Ans: x = 15 km/hr
x-7 = 8 km/hr
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Cheers,
Stan H.
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