Sara needs to needs to trek from an oasis to a destination 10 miles away across a barren desert. However, she finds herself dealing with the following limitations:
a) Crossing one mile of desert requires using 1 gallon of water.
b) She can only carry 6 gallons of water at a time from the water-abundant oasis where she begins.
c) She can drop a water cache (of any amount of water from the supply she is carrying at that moment) at any of the nine stops along the route, and then pick up any part of the cache on a later trip.
The question is: What's the minimum number of times Sara must leave the oasis in order to cross the entire 10 mile span of desert?
1 answer
It appears she needs to make 4 trips to the oasis.