Karnataka Express leaves Bangalore at 5 p.m. and reaches Dharmavaram at 9 p.m. Kurla Express leaves Dharmavaram at 7 p.m. and reaches Bangalore at 10.30 p.m. What time do the trains cross one another?
Option
a) 8.26 p.m.
b) 8 p.m
c) 7.36 p.m.
d) 7.56 p.m
e) None of these

• @SNEHALATHA
  yes the above answer is correct.
  
  Let the total distance be x.
  Time taken by 1st train = 9-5 = 4 hours
  Time taken by 2nd train = 10.30 - 7 = 3.30 hours = 7/2 hours
  Speed of 1st train = distance/time = x/4
  Speed of 2nd train = 2x/7
  
  To find the meeting time of 2 trains,u have to make the starting time of both trains equal.
  Here the starting time of 1st train is 5pm and 2nd train is 7pm.
  So calculate the position of 1st train at 7pm.
  
  Distance travelled by 1st train in 2 hours (5pm to 7pm)
  = speed*time
  = x/4 * 2
  =x/2
  
  So by 7pm the 1st train has already covered a distance of x/2, which implies the distance between the 2 trains at 7pm is remaining x/2 distance(since total distance is x).
  
  Now since both trains start at same time moving towards each other, the time travelled by both trains before meeting is same but the distance travelled is different(since they travel at different speed)
  Let time taken by both trains be 't',
  
  So distance traveled by 1st train = x/4*t
  distance travelled by 2nd train = 2x/7*t
  
  When they meet , the total distance travelled by both is x/2
  
  x/4*t + 2x/7*t = x/2
  15/28*t = 1/2
  t = 14/15
  
  't' is the time travelled by both trains before meeting after 7pm.
  Time of meeting = 7pm + 14/15
  = 7 hours 14/15*60minutes
  =7 hours 56 minutes
  7:56 pm
  
• 10 years agoHelpfull: Yes(9) No(0)
• the answer is 7.56 pm
  as in two hours 1st train covers half of the total distance .
  so remaining is only half of the total distance.
  hence let the time be t
  t(x/4)+t(2x/7)=x/2
  t=14/15 i.e. 56 min
  so total time taken is 2.56 hrs
  so its 7.56pm
• 10 years agoHelpfull: Yes(5) No(4)
• Let x be the distance between both the starting points and the distance traveled by Karnataka and kurla express be x1 and x2 respectively at the time when they meet. So, x1+x2=x......(1)
  Also, time taken by both trains to meet is equal from the moment kurla express starts, but before that Karnataka express has already traveled for 2 hrs. Thus, x1/(x/4) - 2 = x2/(x/3.5).......(2)
  Solving both equations we get time to meet as 14/15 hrs.
  
  
• 9 years agoHelpfull: Yes(1) No(0)
• any1 say this ans s crt or not how to solve this puzzle
• 10 years agoHelpfull: Yes(0) No(0)