Q:

A train travels the distance between station P and Q at a speed of 126 km/h, while in the opposite direction it comes back at 90 km/h. Another train travels the same distance at the average speed of the first train. The time taken by the second train to travel 525 km is:

• 1
  5 hours
• 2
  4 hours 20 min
• 3
  5 hours 20 min
• 4
  4 hours