Train A starts from Meerut at 12:00 pm & reach at Delhi on 2:30 pm & train B starts from Delhi at 12:15pm and reach at Meerut on 2:15pm. So, when both trains crosses each other ?

• Let the distance between Meerut & Delhi be x kms
  &
  let trains meet y hours after 12.15pm
  
  Speed of A= x/150 kms/min.
  speed of B = x/120 kms/min.
  
  Distance covered by A in (y+15) min+distance covered by B in y hours
  =x (x/150)* (y+15) + (x/120) * y = x
  Equating the equations Y=60
  Hence trains meet at 1.15 pm.
• 11 years agoHelpfull: Yes(23) No(6)
• take the distance to be 1 km between Delhi and Meerut.
  so speed of A 1/2.5 and speed of B 1/2.
  relative speed =1/2.5+1/2=9/10.
  after 15 min position of A
  (1/2.5)*(15/60)=1/10 from meerut.
  so distance between A and B at 12.15=9/10.
  relative speed=9/10.
  so the trains meet after 1 hr at 1:15 p.m
• 11 years agoHelpfull: Yes(6) No(2)
• since train A reach in 2.5 hr and B in 2 hr.
  so B's speed (5/4) times of A.
  at 1:15 both will be at middle since B started at 12:15 and A at12:00.
  ans(1:15 pm)
• 10 years agoHelpfull: Yes(5) No(0)
• Ans is :1:05pm ;
  Train Place1_with time ) Place2_(with time ) Time_taken
  A: meerut(12:30pm) delhi(2:30pm) 5/2hr
  B: Delhi(12:15pm) meerut(2:15pm) 2hr
  Now,
  let distance b/w station is D km
  Va=2D/5 kmph;
  Vb=D/2 kmph;
  Now train B started after 15 mint so meanwhile train A traveled D/4 km distance;
  So relative distance between trains is = D-D/4=>3D4;
  Now time of crossing = Relative distance /relative velocity= (3D/4)/(2D/5+D/2)=5/6 hr =>50 min
  Now taking B train in Consideration time of crossing is = 12:15pm+(50min)=1:05pm ;
• 11 years agoHelpfull: Yes(4) No(6)
• (there r two many unknown variables so we need some assumptions...)let distance be 1km between two
  so s1=speed of 1st train=2/5
  s2=speed of 2nd =1/2
  let they meet in x hrs then d1=s1*x
  d2=s2*(x-15/60)
  d1+d2=1
• 11 years agoHelpfull: Yes(2) No(1)
• Ratio of time by train A and B ->150:120
  15:12
  5:4
  Difference between two is 1 part and that 1 part = 15 min(Train B started 15 mins later)
  So 15min*5=75 min after Train A starts is answer i.e 1:15pm
  or 15min*4=60min after Train B starts is answer i.e 1:15pm.
• 5 years agoHelpfull: Yes(2) No(0)
• both the train travel between fixed distance . so let distance = x
  time taken by t1=2.5h and t2=2h
  so x=v1*2.5 and x=v2*2. and v1v2=22.5
  when both the train will meet at that clock watch read same time let t a clock.
  therefore v1*(2.5-t)=v2*t....
  solving this get t=1.11h=66.666 minute therefore 12:15+1.06=13.21 pm = 1.21 pm
• 11 years agoHelpfull: Yes(1) No(4)
• Ratio of time by train A and B ->150:120
• 5 years agoHelpfull: Yes(0) No(2)
• Ratio of time by train A and B ->150:120
• 5 years agoHelpfull: Yes(0) No(2)