View Full Version : Math Help/Check

applemacdude

Jul 6, 2004, 10:13 PM

ok I have a idea wat the answer is but i wanna know if its rite on if i am on track.

Thanks for Help

Raising Rabbits

Judy loves rabbits. She thinks they are cute and cuddly. She knows many other feel the same way so she decides to raise rabits to sell as pets. Easter had just passed and she decides to raise rabbits for a year and sell them next year.

The next day, April 1st, she purchases a pair of newly born rabbits, a male and a female. Judy did her research and learned that in only one month rabbits are young adults and females can get pregnant. She also learned that it only takes a month for rabbits to give birth. She hopes to sell as many rabbits next year.

On june the 1st just like her research said the rabbits had theit first pair of babies. one male and one female. on july 1st the had abother pair of babies again one female/male. on august 1st the original pair had another pair of babies and the their first babies had babies. each time one male/female

If this patterns continues and none of the rabbits die or run away, how many pairs of rabbits will she have to sell after a year?

im not looking for the answer just asking for some guidance if my answer doesnt work out. I would also like to hear your strategys to solving this answer thanks!!

HexMonkey

Jul 6, 2004, 10:29 PM

The number of pairs follows a Fibonacci sequence (this is where the nth term in the sequence is equal to the sum of the two previous terms). This is because, in month n, there will be all the pairs from the previous month, plus the new pairs (which is the same as the number of pairs from two months ago). So there is 1 pair the first month, 1 pair the second, 1+1 pairs the third (because there was 1 pair the previous month, and 1 new pair from the original pair), 2+1 pairs the fourth, 3+2 the fifth etc. Just continue the Fibonacci sequence to find the number after 12 months.

latergator116

Jul 6, 2004, 10:30 PM

First want to find out how many pairs of rabbits the original parents will have by the end of the year (Dec 1). The original rabits' babies should have the number of the parents' rabbits minus 2 (one month for develpment and one month for birth). You want to keep going in the pattern until you get to the rabbits born in October, which will have only have one pair of offspring born by the end of the year. I hope this makes some sense.

Edit: HexMonkey's post better explains it. I am not 100% familiar with the Fibonacci sequence.

Neserk

Jul 6, 2004, 10:32 PM

Draw a picture. It is the easiest way to figure those kinds of problems out unless there is some formula I'm forgetting.

rainman::|:|

Jul 6, 2004, 10:32 PM

yep, they pretty much gave this to you: rabbit breeding is the most common demonstration of the Fibonacci pattern. If it were me, i would spend most of the day in class pointing out that rabbits really aren't often immortal, and then ask about bunny incest. gotta find ways to keep math interesting.

paul

Neserk

Jul 6, 2004, 10:43 PM

yep, they pretty much gave this to you: rabbit breeding is the most common demonstration of the Fibonacci pattern. If it were me, i would spend most of the day in class pointing out that rabbits really aren't often immortal, and then ask about bunny incest. gotta find ways to keep math interesting.

paul

lol... I was thinking about the bunny incest myself. I wanted to ask questions about too much inbreeding. That is the problem with story problems. Too many things they don't tell you!

aus_dave

Jul 6, 2004, 10:55 PM

lol... I was thinking about the bunny incest myself. I wanted to ask questions about too much inbreeding.

Genetic defects would be throught the roof after a few generations - would be like something out of a horror movie I suspect :D.

Neserk

Jul 6, 2004, 10:59 PM

It sad. One of my former student's grandmother ends up with all the neighborhood cats. She got a litter that were probably inbred. They are about half the size of normal cats and obviously not quite right. Either that or some kind of birth defect caused by heaven only know what in the envirnoment...

rainman::|:|

Jul 6, 2004, 11:20 PM

on that topic, my partner and i have raised 4 african pygmy hedgehogs (two pups, two rescues), and there were signs of serious inbreeding in two (the rescues). When exotic animals become a commodity, genetic viability of the line is sacrificed for breeders' space and time concerns. i don't think anyone worries about inbreeding stock anymore... and now, african pygmy hedgies suffer a 1/3 (and rising) chance of developing fatal tumors. Makes me wonder about the cheaper animals: hamsters, guinea pigs, rabbits. since it's usually kids rather than adults that get these animals... of course, they're not rare, but it's still got to happen a lot...

paul

KingSleaze

Jul 6, 2004, 11:55 PM

Who got the number of that truck?

Last week I puchased a burger at Burger King for $1.58. The counter girl took my $2. I dug for my change, pulled 8 cents from my pocket and gave it to her. She stood there holding the nickel and three pennies while looking at the screen on her register.

I sensed her discomfort and tried to tell her to just give me two quarters, but she hailed the manager for help.

While he tried to explain the transaction to her, she stood there and cried.

Why do I tell you this? Because the incident called to my mind the history of teaching math:

Teaching math in 1950

A logger sells a truckload of lumber for $100. His cost of production is 4/5ths of the price. What is his profit?

Teaching math in 1960

A logger sells a truckload of lumber for $100. His cost of production is 4/5ths of the price, or $80. What is his profit?

Teaching math in 1970

A logger exchanges a set ("L") of lumber for a set of money ("M"). The cardinality of set "M" is 100. Each element is worth one dollar. Make 100 dots representing the elements of set "M". The set "C", the cost of production, contains 20 fewer points than set "M". Represent the set "C" as a subset of set "M". Answer this question: What is the cardinality of the set of profits("P")?

Teaching math in 1980

A logger sells a truckload of lumber for $100. His cost of production is $80 and his profit is $20. Your assignment: Underline the number 20.

Teaching math in 1990

By cutting down beautiful forest trees, the logger makes $20. What do you think of this way of making a living? Topic for class participation after answering the question: How did the forest birds and squirrels feel as the logger cut down the trees? (There are no wrong answers).

Teaching math in 2000

A logger sells a truckload of lumber for $100. His cost of production is $120. How does Arthur Anderson determine that his profit margin is $60?

Teaching math in 2005

El hachero vende un camion carga por $100. La cuesta de production es _____.

applemacdude

Jul 7, 2004, 09:06 AM

First want to find out how many pairs of rabbits the original parents will have by the end of the year (Dec 1). The original rabits' babies should have the number of the parents' rabbits minus 2 (one month for develpment and one month for birth). You want to keep going in the pattern until you get to the rabbits born in October, which will have only have one pair of offspring born by the end of the year. I hope this makes some sense.

Edit: HexMonkey's post better explains it. I am not 100% familiar with the Fibonacci sequence.

Thats wat i did....I will ask my mentor if I am correct and try to use he's strategy...

Thanks!

applemacdude

Jul 7, 2004, 07:25 PM

The number of pairs follows a Fibonacci sequence (this is where the nth term in the sequence is equal to the sum of the two previous terms). This is because, in month n, there will be all the pairs from the previous month, plus the new pairs (which is the same as the number of pairs from two months ago). So there is 1 pair the first month, 1 pair the second, 1+1 pairs the third (because there was 1 pair the previous month, and 1 new pair from the original pair), 2+1 pairs the fourth, 3+2 the fifth etc. Just continue the Fibonacci sequence to find the number after 12 months.

Thanks man i talked to my ymentor and i got it...thanks all of u

Dr. Zauis

Jul 7, 2004, 09:25 PM

Teaching math in 2005

El hachero vende un camion carga por $100. La cuesta de production es _____.

:D :D good thing I took spanish in high school otherwise I wouldn't have understood it.

what I remember about Fibonacci sequences is that

A=first term

R= ratio of 1st to 2nd (what u multiply the first by to get the second)

N= nth term

A(R^(N-1))=number of rabbits

wrote a nifty little program for my TI-83 that does all this for me and all I have to do is plug in the numbers. Great for multiple choice tests.

aus_dave

Jul 7, 2004, 11:13 PM

Your assignment: Underline the number 20.

That would keep the pass rate up.

Nice post KingSleaze :D.