If bacterium divides every 20 minutes. How many will there be in a day?
For starters, there are three twenty minute sections in an hour. SInce there are 24 hours in a day you multiply 24 by 3, which is 72. Now you have to write a formula.
You know that the sequence is 1,2,4,8 and so on.
The equation is
the amount of bacterium = 2^number -1
So the answer is 2^71 or 2.36 * 10^21