Question

A train leaves station A toward station B, 24km away and has reach to B in half an hour. If it travels at 45 km per hour for the first quarter of an hour,at what is speed must it travel for the rest of the journey to complete it in time??

Please Solve it guys

Answer 1

So at 45 kmph for first quarter, train will cover 11.25 km.
Now distance left is 12.75 km, and it has to be covered in 15 minutes. So the speed of train should be 4 fold than that of distance left.
Therefore 12.75*4=15 kmph.
Therefore train should have minimum speed of 51 kmph.

Answer 2

Speed = Distance / Time

in fifteen minutes the train covers @ 45km/hr= 45 X 15/ 60= 11.5 km

Total Distance to cover is 24km
distance covered in first 15 min travelling@ 45km/hr = 11.5
 
distance left to cover= 12.75 km  which it need to cover in 15 minutes

So the speed at which it need to cover is 
ie 12.75km X 60/ 15 = 51 km per hr

the train to make up to reach in half an hour to point B need to gather its speed in next quarter to 51 KMPH or Km per hour