2.1.1 Try some yourself
Activity 15
The size of a population of micro-organisms doubles every hour. If there are two of these creatures to start with, how many will there be after five hours?
Answer
After one hour there are 2 × 2 = 4 micro-organisms.
After two hours there are 2 × 4 = 8, or 2 × 2 × 2 = 23.
After five hours there are 2 × 32 = 64, or 2 × 2 × 2 × 2 × 2 × 2 = 26.
So there will be 26 = 64 after five hours.
(Note: if you gave 32 as your answer, maybe you forgot that there were 2 organisms to start with.)