Q:

Two trains starts from place A and B, 450 km apart towards each other. Both trains start simultaneously. A crow sitting on one train start flying at the same time towards the other train and as soon as it reaches the second train, it flies back to the first train and it continues in this manner flying backward and forwards from one train to the other until the train meet. Both train travel  at a speed of 45 km / h and the crow flies at 100 km / h total distance covered by the crow will be 

• 1
  400 km
• 2
  360 km
• 3
  450 km
• 4
  500 km