A train travelling at a speed of 75 mph enters a tunnel 3½ miles long. The train is ¼ mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges?

Given

• Speed = 75 mph
• Tunnel length = 3.5 miles
• Train length = 0.25 mile

Total distance to clear tunnelDistance = 3.5 + 0.25 = 3.75 milesTime (hours) = 3.75 / 75 = 0.05 hTime (minutes) = 0.05 × 60 = 3 minutes

Note: Add train length to tunnel length for full clearance.