Originally posted by Codfish
You have 3,000 bananas and a camel which can carry at most 1,000 bananas at a time. The camel eats a banana before moving a unit. You want to transport the bananas 1,000 units. What is the maximum number of uneaten bananas that you can move 1,000 units?
The first unit for the 3000 bananas will take the camel 3 trips, and thus 5 bananas (one banana for each trip away AND one for each trip back)
The second unit will again take 5 bananas out of the pile, making it a total of 2*5 = 10 bananas less.
The 199th unit will again take 5 bananas from the total. The camel has eaten 5*199 = 995 bananas. You have 2005 bananas left now.
The 200th unit will also take 5 bananas. 2000 left.
The 201st unit will now only take 3 bananas.
The 533 unit will take another 3 bananas leaving 2000 - 333*3 = 1001 bananas.
Feed the camel a banana and he'll take the other 1000 on his 534th unit.
From now on it's a banana for every unit he still has to do. He has 466 units left to travel.
This means you will arrive at the end of your journey with 534 bananas.