<PRE><B>Question 741233</B>
d=210
original speed=x
increased speed = x+5

Time original -time with increased speed = 1

t=d/r

{{{210/x-210/(x+5) =1}}}


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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