Five balloonist will travel up to a 1000 ft. high plateau to see the sunrise.
Each carry a rope and a 1, 2, 3, 4, 5 Lbs sandbag so that they ascend
at 5, 4, 3, 2, 1 ft/sec respectively.(the hellium balloons are similar)
In order to arrive altogether at the same time to the top they may use the
ropes to pass or exchange their sandbags with the others at any time.
Starting all on the ground, how would they plan the trip with minimum
passes or exchanges? (()) (()) (()) (()) (()) \/__\/__\/__\/__\/