Thread: find time in rate problem

two trains 200 meters and 150 meters are running on the parallel rails at this rate of 40km/hr and 45km/hr.in how much time will they cross each other if they are running in the same direction

Originally Posted by hena

two trains 200 meters and 150 meters are running on the parallel rails at this rate of 40km/hr and 45km/hr.in how much time will they cross each other if they are running in the same direction

I'm assuming by cross you mean pass (they won't cross because they're parallel but they will pass) and that 200m is the starting point of the 40km/h train and 150m is the starting point of the 45km/h train.

40h + 0.2 = 45h + 0.15

5h = 0.05

h = 0.01

0.01 * 60 * 60 = 36 seconds

but the options they gave for this que is...
197 sec,212sec,252sec,312sec

Hello,

Originally Posted by hena

but the options they gave for this que is...
197 sec,212sec,252sec,312sec

Can you rephrase the original text, please ? Because it's really unclear...

am not getting a proper answer...
this is the way they have given me

Originally Posted by neha1

am not getting a proper answer...
this is the way they have given me

i will rephrase it once again
two trains 200 meters and 150 meters are running on the parallel rails at this rate of 40km/hr and 45 km/hr.in how much time will they cross each other if they are running in the same direction?

I think you mean this...

The 150m train starts at the back of the 200m train but moves 5kmh faster. For how long are they overlapping?

They're overlapping For 350 metres (The 200m to get the front of the faster train to the front of the other train, then the 150m to get the back of the faster train in front of the front of the slower train).

Every hour, the faster train catches up 5km on the slower one. How long does it take to catch up 0.35 km on it?

(0.35/5) * 60 = 4.2 minutes = 252 seconds.

is there any other option for this