# find time in rate problem

• May 23rd 2008, 11:38 PM
neha1
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
• May 24th 2008, 01:27 AM
sean.1986
Quote:

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
• May 24th 2008, 04:22 AM
neha1
but the options they gave for this que is...
197 sec,212sec,252sec,312sec
• May 24th 2008, 04:41 AM
Moo
Hello,

Quote:

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...
• May 25th 2008, 08:24 AM
neha1
plz help
am not getting a proper answer...
this is the way they have given me
• May 25th 2008, 06:31 PM
neha1
Quote:

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?
• May 25th 2008, 09:40 PM
sean.1986
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.
• May 26th 2008, 05:27 PM
neha1
any other suggestion plz
is there any other option for this