QUESTION 11:
How many rabbits are there at the end of month 4?
The one mature female rabbit gives birth to one baby female rabbit during the third month. So there is a total of two female rabbits (and several males).
The new chart shows this. At the end of month three there is 1 mature female rabbit and 1 baby female rabbit for a total of two female rabbits.
| N | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Females | 1 | 1 | 2 |
If you look under month 2 you see how many mature female rabbits there are in month 4. Since it takes rabbits two months to become mature, every rabbit listed for month N will be mature in month N+2. Each one of these rabbits will produce one new baby rabbit in month N+2.
If you look under month 3 you see how many total female rabbits there are at the start of month 4.
Add the rabbits in month 2 (which equals the number of babies born during month 4) to the rabbits in month 3 to get the total number of rabbits ate the end of month 4.
How many rabbits are there at the end of month 4?