SOLUTION: HELLO, I AM IN COLLEGE AGAIN AND HAVING THE WORST TIME FIGURING OUT STOPPING DISTANCE WORD PROBLEMS.The question is The stopping distance of a car after the brakes are applied v

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Question 395469: HELLO,
I AM IN COLLEGE AGAIN AND HAVING THE WORST TIME FIGURING OUT STOPPING DISTANCE WORD PROBLEMS.The question is The stopping distance of a car after the brakes are applied varies directly as the square of the speed r. If a car traveling 60 mph can stop in 200 feet, how many feet will it take the same car to stop when it is traveling 40 mph? The issue I am having is they want a fraction for an answer and I keep getting a non-fraction answer. I have tried to switch out the problem on the homework, but I CANT seem to get passed the second half. I would be very, sincerely helpful for any step by step , what the numbers mean, and where you got them guidance. The help on the assignment does not explain how the numbers are calculated or where they come from, and I have divided and multiplied and it is still a mystery.
Than you for the time and help,

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The stopping distance of a car after the brakes are applied varies directly as the square of the speed r. If a car traveling 60 mph can stop in 200 feet, how many feet will it take the same car to stop when it is traveling 40 mph? :
:
Use ratio, relationship of speed to stopping distance
r%5E2%2Fs
:
let s = stopping distance at 40
60%5E2%2F200 = 40%5E2%2Fs
3600%2F200 = 1600%2Fs
cross multiply
3600s = 1600 * 200
3600s = 32000
s = 320000%2F3600
s = 88.89 ft to stop at 40 mph
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