Friday, May 14, 2010

How long would the two lilies have taken to cover the entire pond?

A certain water lily grew extremely quickly and doubled its surface area each day. At the end of the thirtieth day, it had entirely covered the pond in which it lived. If a second water lily, identical to the first, had been in the pond, how long would the two lilies have taken to cover the entire pond?

How long would the two lilies have taken to cover the entire pond?
12 days, divide the pond in two parts, if you think, you can see that on day 12, 1 lily will have half the pond covered, bacause it will double the next day


so if you have 2, on day twelve they will each half the pond covered making a whole pond between them
Reply:1 day less - 29 days. Reason: A the end of the first day with the first pool you have 2 lilies.
Reply:29 days





The growing is exponencial





1, 2, 4, 8, ..., 2^29 in 30 days





If you put two plants, then you have 2, 4, 8, 16, ... 2^29 in 29 days





Ana


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