A certain bacteria colony doubles in size every day for 10 days, a which point it reaches the limit of its habitat and can no longer grow. If two bacteria colonies start growing simultaneously, how many days will it take them to reach the habitat’s limit?
Answers
A) 6.33
B) 9
C) 10
D) 15
E) 19
Case 1: Consider the bacteria num to be B. As it doubles every day, number of bacteria at the end of each day would be   Day 1 – B   Day 2 – 2B   Day 3 – 4B   Day 4 – 8B   .   .   .   Day 10 – 2^19 B   It can be implied that the capacity of the habitat is 2^19 B.   Case 2: There are 2 bacteria which keep doubling every day. So, the count would be   Day 1 – 2B   Day 2 – 4B   Day 3 – 8B   .   .   .   Day 18 – 2^18 B   Day 19 – 2^19 B --&gt; this is the point where the habitat is filled to its capacity.   Hence, 9 is the answer   9
<result>B</result>
A certain bacteria colony doubles in size every day for 10 days, a which point it reaches the limit of its habitat and can no longer grow. If two bacteria colonies start growing simultaneously, how many days will it take them to reach the habitat’s limit?