Yeast is doubling in the container every minute. Starting with a small amount it takes 80 minutes to fill the container. How long will it take to fill one half of the container?

The answer to your question is 79 min

Step-by-step explanation:

We know that a yeast doubles every minute.

If half of the container is filled, that means that to the next minute it will be filled.

One minute before 80 is 79, during this minute yeast population doubles and the container will be filled.