Question

the population of a bacteria culture doubles in number every 12 minutes. the ratio of the number of bacteria at the end of 1 hour to the number of bacteria at the beginning of the hour is? ...?

Answer 1

32

Explanation:

Let X be the number of bacteria at the initial time.

At 12 minutes = 2 X

At 24 minutes = 4X

At 36 minutes = 8X

At 48 minutes = 16X

At 60 minutes = 32X

The ratio between the final and the initial instant will be: 32X / X = 32

Answer 2

Let's say the number of bacteria you initially have is "a."  The number of bacteria doubles every twelve minutes, which means that it doubles 5 times in an hour.  You have(2)(2)(2)(2)(2)a=a∗2^5=32a at the end of the hour.  You started out with only a.  This means your ratio is 32a/a = 32.