(this is an extra credit assignment for my class, and I really need it)
On January 1st, two rats go onto an island, male and female. The female has 10 babies, 5 males and 5 females. Every female rat waits 120 days before reproducing, and after that, it's every 40 days until reproduction. If all the rats survive, how many rats will be on the island after a year, on January 1st.