Two trains A and B havins speeds 5km/h and 7km/h resp. approaches each other from city Aurangabad and Jhansi.The distance b/w the cities is 27km.How much time they will take to meet each other at mid way of city second time?
opt:
a)27
b)10
c)40.5
d)None of these

• train a will cover 27km n 5.4hrs
  train b will cover 27km n 3.85 hrs
  taking lcm of both we get 20.25hr
  so they will meet after 20.25hrs fpr the 1st time n midway
  so for second time it will b 20.25*2=40.5
  so 40.5hrs s the ans
• 10 years agoHelpfull: Yes(23) No(13)
• firstly combine d speed of d two. it will give u d time of 1st meeting
  27/(5+7)=27/12=2.25 hr.
  so they will meet after 2.25 hr.
  now in this A will cover d distance upto 2.25*5=11.25
  and B will cover 2.25*7=15.75
  now in another 2nd 2.25 hr. they will cover d same distance
  so A covers 22.5 km and B will cover 31.5 km.
  in other 2.25 hr. they both will return and cover a distance upto 20.25km. and 6.75 from their respective sides
  which will be their 2nd meeting point
  so they will take time = 3*2.25=6.75 hr.
• 10 years agoHelpfull: Yes(22) No(1)
• ans(C)40.5
  the distance travel by the train A and B is from these values,
  27/2,27*3/2,27*5/2,....27*(2*n+1)/2,
  
  for train A: 27*(2n+1)/2=5*t
  for train B: 27*(2k+1)/2=7*t
  for n=7 and k=10
  t=27*3/2=40.5
  
  
• 10 years agoHelpfull: Yes(6) No(4)
• we are asked about the total time taken when they meet for the 2nd time
  therefore,for first journey both trains travel a distance of 27=27+27=54km
  now,when they meet again they must have together travelled 27 more kms as they meet in between
  which makes it 54+27=81 km
  relative speed =5+7=12kmph
  time=81/12=6.75 hrs.
• 10 years agoHelpfull: Yes(5) No(0)
• in 6 hr A will cover 42 km which is ( 42-27=15 in return way) and B will cover 30 km which is (30-27=3 in return way)
  so remaining km is (27-15-3=9)
  so v=d/t
  t=d/v
  t=9/(5+7)
  t=3/4 h
  
  total time when they second meet= 6+3/4 =6 hr 45 mints
• 10 years agoHelpfull: Yes(4) No(5)
• Ans=d
  as all discussed that train will meet for 1st time in 20.25 hr. How it is possible.Maximum tme taken by train of speed 5km/hr will be 5.4hr to cover 27 km and to cover 54 km will be 10.8 hr.take total distance =54 km bacause in question it is mention 2nd time.
  take total distance cover by B=x km in T time
  And by A=(54-x)km in T time.
  (54-x)/7=x/5.
  x=22.5 km.
  After covering 22.5 km they will meet.
  Time=22.5/5=4.5hr.
  Ans =4.5hr.
  
• 10 years agoHelpfull: Yes(1) No(1)
• ->for 1st meeting relative speed will be s1+s2 since trains are moving in opposite direction i.., 12 km. and time taken will be 27/12
  ->after 1st meeting they will get separated and again start moving in opposite direction again relative speed will be s1+s2 i.e 12,again time taken will be 27/12.
  ->after going to end point they will start moving towards each other with relative speed of 12 since they are moving in opposite direction again. time taken will be 27/12.
  ->therfore total time taken will be 27/12+27/12+27/12
  =3*27/12
  =6.75 hr
  
• 10 years agoHelpfull: Yes(1) No(0)