let's say the initial population is "a" amount of flies, so then
[tex]\bf \begin{array}{llll}
\stackrel{passed}{hours}&amount\\
---&--------\\
0&a\\
4&2a\\
8&2(2a)\\
12&2(2\cdot 2a)\\
16&2(2\cdot 2\cdot 2a)\\
20&2(2\cdot 2\cdot 2\cdot 2a)\\
24&2(2\cdot 2\cdot 2\cdot 2\cdot 2\cdot 2a)\\
&2^6\cdot a
\end{array}[/tex]
notice, the population has grown by to 2⁶ of the original amount.
