<PRE><B>Question 937744</B>
A train travels 300km at a constant speed of Vkm/h. If the train had travelled 5km/h faster, the journey would have taken two hours less. Find the speed of the train travelling at the lower speed.
***
let v=slower speed of trains
v+5=faster speed of train
travel time=distance/speed
..
{{{300/v-300/(v+5)=2}}}
lcd:v(v+5)
300v+1500-300v=2v(v+5)
1500=2v^2+10v
2v^2+10v-1500=0
v^2+5v-750=0
(v+30)(v-25)=0
v=25
lower speed of train=25 km/h</PRE>