Question

Train R takes 5 hrs less than train S fore covering a distance of 750km.If the average speed of train R is 25 km /hour more than that of train S find the average speed of both the trains

Answer 1

Let S1 and S2 be speed of both the trains represented by X

Answer 2

Answer:

Speed of Train S = 50 km/hr & Speed of train R  =75 km/hr

Step-by-step explanation:

Given: Distance travel by Both train is 750 km

To find: Speed of both trains

Let Speed of train S = x km/hr

and Speed of train R = x + 25 km/hr

using speed, distance and time formula we get

Time taken by train S = $\frac{750}{x}$

Time taken by train R = $\frac{750}{x+25}$

According to question,

$\frac{750}{x}\,-\,\frac{750}{x+25}\,=\,5$

$\frac{750x+750\times25-750x}{x(x+25)}\,=\,5$

$18750\,=\,5\times(x^2+25x)$

$5x^2+125x-18750=0$

$x^2+25x-3750=0$

$x^2+75x-50x-3750=0$

$x(x+75)-50(x+75)=0$

$(x+75)(x-50)=0$

⇒ x = -75 and x = 50

Speed cannot be negative therefore we select value of x = 50

⇒ Speed of train S = 50 km/hr  &   Speed of train R = 75 km/hr

Therefore, Speed of Train S = 50 km/hr & Speed of train R  =75 km/hr