It takes 30 days to fill a laboratory dish with bacteria. If the size of the bacteria doubles each day, how long did it take for the bacteria to fill one quarter of the dish?
Options.
A) 10 days  B) 14 days  C) 24 days  D) 28 days  E) 29 days
The bacteria doubles each day, so after 29 days, the dish was half full.   After 28 days, the dish was one quarter full.   The answer is 28 days.
<result>D</result>
It takes 30 days to fill a laboratory dish with bacteria. If the size of the bacteria doubles each day, how long did it take for the bacteria to fill one quarter of the dish?