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 Amoebas! (Posted on 2002-06-20)
An amoeba propagates by simple division; each split takes three minutes to complete. When such an amoeba is put into a glass container with a nutrient fluid, the container is full of amoebas in one hour.

How long would it take for the container to be filled if we start with not one amoeba, but two?

 See The Solution Submitted by carlina Rating: 3.3000 (10 votes)

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 Puzzle Solution | Comment 12 of 13 |

The total number of amoebae at the end of 3 minutes is 2. The number of amoebae will double from every three minutes thereafter, to eventually fill up in one hour.

If we had two amoebae to start with, then the number of  amoebae at the end of 3 minutes would have been  4. Since the number will double every three minutes, it follows that the container will be twice full in one hour, so that it will take precisely 60-3=57 minutes to fill the container.

Edited on March 9, 2008, 10:48 pm
 Posted by K Sengupta on 2008-03-09 12:20:24

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