Two friends decided to get together and start riding bikes towards each other, both at a speed of 6 km/hr (starting at the same time). The live 36 km apart and hence will meet halfway.
One of them have a pet pigeon and it starts flying the instant the friends start traveling. The pigeon flies back and forth between the two friends, at a speed of 18 km/hr until the friends meet.
How much distance (in km) will the pigeon travel?
The time for which pigeon will fly is equal to the time taken by friends to meet (after they start from their homes).
Relative speed of friends = 6 + 6 = 12 km/hr (traveling toward each other)
Distance = 36 km
Time taken to meet = 36/12 = 3 hrs.
Pigeon is flying at a speed of 18 km/hr.
In 3 hrs it will cover a distance of 18 * 3 = 54 km.