SOLUTION: A motor boat traveling at 18 miles per hour traveled the length of a lake in one-quarter of an hour less time than it took when traveling at 12 miles per hour. What was the length

Question 255021: A motor boat traveling at 18 miles per hour traveled the length of a lake in one-quarter of an hour less time than it took when traveling at 12 miles per hour. What was the length in miles of the lake?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A motor boat traveling at 18 miles per hour traveled the length of a lake in one-quarter of an hour less time than it took when traveling at 12 miles per hour. What was the length in miles of the lake?
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Let the length of the lake be x miles.
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Fast-trip DATA:
rate = 18 mph ; distance = x miles ; time = x/18 hr.
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Slower-trip DATA:
rate = 12 mph ; distance = x miles ; time = x/12 hr.
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Equation:
slow time - fast time = 1/4 hr
x/12 - x/18 = 1/4
Multiply thru by 36 to get:
3x - 2x = 9
x = 9 miles
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Cheers,
Stan H.
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