Rat Populations
Ian deGrouchy
Mrs. Psitos
Math IMP 2H
18 December 2007
Growth of Rat Populations This POW is about the growth of a rat population over a year. Two rats, one male and one female, are put on an island that has ideal conditions for rats. The female rat has a litter of six rats the first day, and will have a litter every forty days after that. There are three important things to remember, and they are that the number of rats in every litter is six, three females and three males. Secondly, every female born on the island will have her first litter 120 days after she is born, and she will have a litter every forty days thereafter. Lastly, no rats will die in the first year. I first decided to make a chart because I knew that I needed to keep track of the number of female rats having litters, the number of total rats born, and the number of female rats born that can have litters before the end of the year. This is what the chart looked like:
Day Number of rats having litters Total number of rats Number of female rats born that can have litters …show more content…
I did this because since those are the number of females having litters, and each female has six rats in each litter, then I would multiply the total number of females having litters by six. For example, on day 241 there are 22 females having litters. So, I multiplied 22 by 6 and got that total number of rats born that day was 132. Then, to find out the number of females, I divided the total number of rats born by two because half of the litters are females. So, on day 241, there are 66 females born that day because half of 132 is 66. After I wrote the chart, I was able to come to a solution for the POW. I added the number of rats born each day and got 1,806. Then, I added 2, for the original rats, and got an answer of 1,808 rats will be on the island. To evaluate this, I thought about a few questions, which
Mrs. Psitos
Math IMP 2H
18 December 2007
Growth of Rat Populations This POW is about the growth of a rat population over a year. Two rats, one male and one female, are put on an island that has ideal conditions for rats. The female rat has a litter of six rats the first day, and will have a litter every forty days after that. There are three important things to remember, and they are that the number of rats in every litter is six, three females and three males. Secondly, every female born on the island will have her first litter 120 days after she is born, and she will have a litter every forty days thereafter. Lastly, no rats will die in the first year. I first decided to make a chart because I knew that I needed to keep track of the number of female rats having litters, the number of total rats born, and the number of female rats born that can have litters before the end of the year. This is what the chart looked like:
Day Number of rats having litters Total number of rats Number of female rats born that can have litters …show more content…
I did this because since those are the number of females having litters, and each female has six rats in each litter, then I would multiply the total number of females having litters by six. For example, on day 241 there are 22 females having litters. So, I multiplied 22 by 6 and got that total number of rats born that day was 132. Then, to find out the number of females, I divided the total number of rats born by two because half of the litters are females. So, on day 241, there are 66 females born that day because half of 132 is 66. After I wrote the chart, I was able to come to a solution for the POW. I added the number of rats born each day and got 1,806. Then, I added 2, for the original rats, and got an answer of 1,808 rats will be on the island. To evaluate this, I thought about a few questions, which