There is a certain bacterium in a bottle, and the bacterium splits from one to two within 2 minutes. After half an hour, the bacterium fills the bottle. If initially there are 4 bacteria in the bottle, how many minutes will it take to fill it? full bottle.
一瓶子中装有一个某种细菌，这种细菌在2分钟内由一个分裂成两个，半小时后，细菌装满了瓶子，若最初瓶子中装有4个这种细菌，需多少分钟装满瓶子．
<gadget id="calculator">30 - 2 - 2</gadget>
<output>26</output>

<result>26</result>