math

A type of bacteria doubles in number every 12 hours. After 2 days, there are 48 bacteria. How many bacteria were there at the beginning of the first day.

asked by Taylor
  1. 2 days is 4 doublings, or 16 times the original amount.

    So, there were 3 to begin.

    posted by Steve
  2. Thank you Steve.
    But I want to know how to show it.
    Thanks once again

    posted by Taylor
  3. every 12 hours, the population doubles. So, if it starts out as p, then after t hours, we have

    p*2^(t/12)

    for t=48, then,

    p*2^(48/12) = 48
    p*2^4 = 48
    16p = 48
    p = 3

    posted by Steve

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