Problem - 4639
$\textbf{Bottle of Bacteria}$
A scientist puts a bacteria in a bottle at exactly noon. Every minute the bacteria divides into two and doubles in size. At exactly $1$ PM the bottle is full. At what time is the bottle half full?
$\textbf{Answer}$
The answer is $12:59$ because it takes just $1$ minute to double the size.
$\textbf{Note}$
Brain teasers usually do not involve tedious calculation. Therefore, if a problem appears to require lengthy computation, it is more likely you are on the wrong track. Do not fall into the trap of over-thinking.