Question

The stopping distance d of a car after tehe brakes are applied varies directly as the square of the speed r. If a car traveling 50 mph can stop in 140 ft. How many feet will it take the same car to stop when it is traveling 70 mph?
I did everything and I got 6860/25, how do I convert that to lowest terms, they are not looking for a mixed fraction, which is the only thing I know how to do. Thank you

Answer 1

r=140 (70/50)^2= 140*49/25=274 ft

Answer 2

thanks, but they said to use form,140=k*50^2, then I got 140=k(2500) which ends up being k=14/250. The equation variation is d=14/250*r^2 which give us d=14/250*70^2 or 6860/25. I just didn't know how to convert to lowest terms. Can you help me with this? Other examples I got wrong are 9800/36 I was suppose to convert to 2450/9, I don't know how they got this, do you?