made easy cbt 1 2019

Question

A train after travelling for 50 km meets with an accident and then proceeds at 3/4th of its former speed and arrives the destination 35 minutes late. Had the accident occured 24 km farther, it would have reached the destination only 25 minutes late. what is the speed of train in kmph

Answer 1

Let $s$ and $d$ be the original speed of train and total distance. Therefore,

$\left ( 50/s \right ) + \left ( d-50 \right )/\left ( 3s/4 \right ) = \left ( d/s \right )+35/60$ ---(1)

$\left ( 74/s \right ) + \left ( d-74 \right )/\left ( 3s/4 \right ) = \left ( d/s \right )+25/60$ ---(2)

 

Solving Equation (1) and (2), we get $s$ $=$ $48 km/hr$.