The Bacteria in a 8 liter container double every minute. After 55 minutes the container is full. how long did it take to fill half the container.?
If I am understanding the question correctly, 55 doublings will give you the full 8 L. Therefore, 2^55 = 8L
How long did it take to get 4L?
8L/2 = 4L. What you do to one side of an equation, you need to do to the other, so you would need to find 2^55 /2
This would be 2^55 /2^1 ----> 2^(55-1) = 2^54
So it would take 54 minutes to fill half the container.
Check: If at 54 minutes, the container is half full, what is the volume after 55 minutes (1 doubling)? 1/2 * 2 = 1, so the container would be full.
Hope this helps