SOLUTION: a semi truck travels 300 miles through flat land in the same amount of time it travels 180 miles through the mountain. the rate of the truck is 20 miles per hour slower in the moun

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Question 109791: a semi truck travels 300 miles through flat land in the same amount of time it travels 180 miles through the mountain. the rate of the truck is 20 miles per hour slower in the mountains than in the flat land. find the flat land and mountain rates.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
a semi truck travels 300 miles through flat land in the same amount of time it travels 180 miles through the mountain. the rate of the truck is 20 miles per hour slower in the mountains than in the flat land. find the flat land and mountain rates.
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Flatland DATA:
distance = 300 miles; rate = x mph ; time = d/r = 300/x hrs.
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Mountain DATA:
distance = 180; rate = x-20 mph ; time = d/r = 180/(x-20) hrs
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EQUATION:
time = time
300/x = 180/(x-20)
5/x = 3/(x-20)
5x-100 = 3x
2x = 100
x = 50 mph (Flatland rate)
x-20= 30 mph (Mountain rate)
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Cheers,
Stan H.