A group of N people holidaying in the seaside town A decided to visit their friends staying town B which is N km (kilometres) along the coast.

Some of the group walk along the cliff path at a steady N km an hour. The rest, one less in number than the walkers, go by car which (not counting stops) averages 10 times the speed of the walkers.

The road is much longer than the cliff path.

Map.

Those in the car stop for N minutes for fuel, then N times as long as that for coffee, and are further delayed for N minutes by a flock of sheep. They finally reach town B one minute before the walkers.

How long is the road between towns A and B ?