two guns were fired from the same place at an interval of 13 minutes but a person in a train approaching the place hears the second report 12 minutes 30 seconds after the first. find the speed of the train in kmph, supposing that sound travels 330 metres per second

1) 33 approx
2) 43 approx
3) 47 approx
4) 49 approx

• Difference of time = 13 min-12 mins. 30 secs = 30 secs.
  Distance covered by man in 12 mins. 30 secs = distance covered by sound in 30 secs
  = 330*30 = 9990m.
  Hence, speed of man = 9900/12 min. 30 secs;
  = 9900m/750 secs
  = 9900*18/750*5 kmph
  = 47.5 kmph.
  =47kmph
• 7 years agoHelpfull: Yes(1) No(0)
• let the speed of the train be x m/sec. Then,
  
  Distance travelled by the train in 10 min. = Distance travelled by sound in 30 sec.
  
  x x 10 x 60 = 330 x 30 x = 16.5
  
  
  Speed of the train = 16.5 m/sec = 16.5 x18/5
  km/hr = 59.4 km/hr
  
• 10 years agoHelpfull: Yes(0) No(2)
• distance travelled by sound = 13-12.30 = 30 sec
  
  train travels = 330*30metre in 12 1/2 min
  
  speed of train = (330* 30 *2*60) / 25*1000
  
  =47(13/25)
  
  so 47 approximate
• 9 years agoHelpfull: Yes(0) No(0)