<PRE><B>Question 893140</B>
If a train travels 5 km/h faster than its normal speed, it would take 1 hour less to
travel 210 km. What is the normal speed? 
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let x=normal speed
x+5=faster speed
Travel time=distance/speed
{{{210/x-210/(x+5)=1}}}
lcd:x(x+5)
210x+1050-210x=x(x+5)=x^2+5x
x^2+5x-1050=0
(x+35)(x-30)=0
x=-35(reject)
or
x=30
What is the normal speed? 30 km/hr</PRE>