SOLUTION: if a car travelled 5 kilometers an hour faster it would take an hours less to travel 210 km,what is the original speed of the car and what time does it take?

Question 741233: if a car travelled 5 kilometers an hour faster it would take an hours less to travel 210 km,what is the original speed of the car and what time does it take?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
d=210
original speed=x
increased speed = x+5
Time original -time with increased speed = 1
t=d/r

simplify
multiply equation by x(x+5)
210(x+5)-210x=x(x+5)
210x+1050-210x=x^2+5x
x^2+5x-1050=0
x^2+35x-30x-1050=0
x(x+35)-30(x+35)=0
(x-30)(x+35)=0
x= 30 OR -35
ignore negative
There you are

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