math
posted by Taylor
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.

Steve
2 days is 4 doublings, or 16 times the original amount.
So, there were 3 to begin. 
Taylor
Thank you Steve.
But I want to know how to show it.
Thanks once again 
Steve
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
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