<PRE><B>Question 263137</B>
After an accident police determine the speed at which the car had been traveling based on the length of the skid marks the car left on the road. 
The police use the following formula: r= 2(over)/(5L)^-1/2, where r is the speed of the car, in miles per hour, and L is the distance of the skid marks, in feet. 
A. Solve the equation r= 2(over)/(5L)^-1/2 for L. (Apply rule of negative and fractional exponents before solving for the variable L.)
r= 2(over)/(5L)^-1/2 for L
r = 2(5L)^(1/2)
(5L)^(1/2) = (r/2)
(5L) = (r/2)^2
5L = r^2/4
L = r^2/20
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r is the speed of the car in miles per hour, 
L is the distance of the skid marks, in feet. 
 
B. How far will a car skid at 65 mph? Round your answer to the nearest whole, feet if necessary. 
L(65) = 65^2/20 = 211.25 ft

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Cheers,
Stan H.</PRE>