A train leaves Delhi at 6.00 a.m. and reaches Agra at 10.00 a.m. Another train leaves Agra at 8.00 a.m. and reaches Delhi at 11.30 a.m. At what time do the two trains cross each other if the distance between Delhi and Agra is 200 km?
a) '8.45 a.m.' b) '8.56 a.m.' c) '9.20 a.m.' d) 9.56 a.m.'

• Speed of first=s=200/4=50km/h
  Speed of second=S=200/3.5=400/7km/h
  Till 8 A.M. first one has already covered 50 x 2=100 Kms
  So now both are 100 km apart
  They are approaching each other
  So relative speed=50+400/7=750/7 Km/h
  Time=100/(750/7)=700/750=14/15 hours=14x60/15=56 minutes
  So they will cross each other at 8.56A.M
• 9 years agoHelpfull: Yes(31) No(0)
• First train has covered 100 kms in 2 hrs up to 8AM.
  Balance 100 kms is covered by 2 trains in opposite direction in x hrs ( say), then
  50x+ x*400/7 = 100
  x= 14/15 hrs or 56 mins
  
  so they will meet at 8:56 AM.
• 11 years agoHelpfull: Yes(13) No(5)
• ans : b) 8:56 a.m
• 11 years agoHelpfull: Yes(3) No(2)
• optn b i.e 8.56
• 11 years agoHelpfull: Yes(2) No(1)
• speed of 1st train is 200/4=50km/hr (time taken to 1st train to reach agra is 4 hrs)
  speed of 2nd train is 200*2/7=400/7 km/hr(time taken to 2nd train to reach delhi is 3hrs 30minutes)
  distance covered by 1st train at 8:00AM=50*2=100kms
  so relative speed=50+400/7=750/7 km/h
  time=100/(750/7)=700/750=14/15=(14/15)*60=56 minutes
  8hrs 56 minutes is ans
  
  
• 7 years agoHelpfull: Yes(1) No(0)
• d
  aftr 2 hrs 2 train starts
  by 9 1st train at 150 km 2nd at 57 1/7 km
  by solving 9 20
• 11 years agoHelpfull: Yes(0) No(3)
• Let delhi train be D
  Let agra train be A
  Time taken by D is 4hrs
  Time taken by A is 3.5hrs
  Speed of D is 200/4=50
  Speed of A is 200/3.5=400/7
  Total speed of both train is 50+400/7=
  750/7
  Distance covered by d in 2hrs= 50*2=100
  The remaining distance to be covered is 200-100=100
  Time taken by two train to cross each other i.e100/750/7=14/15hrs is14/15*60=56 minutes
  Hence, the two train will cross each other at 8:56 i.e option(b)
• 8 years agoHelpfull: Yes(0) No(0)
• time of 1st train=10:00-6:00=4hrs
  time of 2nd train=11:30-8;00=3.5hrs
  Let the speed of the 1st train =d/t=200/4=50km/hr
  Let the speed of the 2nd train =d/t=200/3.5=400/7km/hr
  1st train leaves 2hrs before the 2nd train so 1st train already completed 100kms
  so distance will be 100km
  relative speed = speed of t1+speed of t2
  speed = 50+400/7=750/7
  time = d/s=100*7/750
  time=70/75=14/15 hrs =14*60/15 mins = 56mins
  So they will cross each other at 8.56A.M
• 4 years agoHelpfull: Yes(0) No(0)