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This problem trains for: SAT-I, AMC-8, AMC-10, GMAT, Math Kangaroo 5-6, Math Kangaroo 7-8, Math Kangaroo 9-10.

As a result of a powerful storm the fresh water supply of Captain Cousteau's "Odyssey" has been partially spoiled. Originally, the supply would have supported 11 crew for 20 days. Now, only 10% of the fresh water is still usable. The nearest port where they can buy fresh water is about 4 days away but there is an island in sight where there is a natural stream. What is the maximum number of people that must be left to wait on the island?

(J-Y. Cousteau was a French explorer and inventor. His was a wonderful life about which you should read.)

If the supply would have supported 11 people for 20 days then it would have supported 1 person for 220 days.

If only 10% of the supply is still available, then it would support 1 person for 22 days.

How many persons x would it support for 4 days?

equation

Solving for x:

equation

The number of persons is the largest integer that is smaller than 5.5, i.e. only 5 people can go while the rest must remain on the island.