<PRE><B>Question 462226</B>
Grade of a Highway The grade x of a hill is a measure of the steepness and r responds to the slope of the highway. The accompanying figure shows a grade of x= 10/100 = 10% because the road rises 10 feet for every 100 feet of horizontal run. The braking distance D in feet for a car traveling 60 miles per hour on a wet uphill grade is given by
D(x) = 3600/30x + 9 
(b) Find the grade x for a braking distance of 300 feet
Solve: 300 = (3600/30x)+9
291 = 3600/30x
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x = 3600/(30*291)
x = 0.4124
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Cheers,
Stan H.
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