A modified Fibonacci problem

[desibaba]

Here goes:

Rabbits mate and have offspring once a year, and each time they multiply, they have exactly two male offspring and two female offspring. If you start with one male and one female rabbit, how many rabbits will you have after two years if the offspring mate as well ?

I answered 18 but the answer key says I am wrong. Help would be greatly appreciated !

[OfficeShredder]

The answer is six. After the first generation, they can't mate anymore because that goes against incest laws.


Here's how it really works:

Year 1:
Two rabbits mate. Eight rabbits are now around.

Year 2:
All four pairs mate (including the first pair), creating 16 more rabbits. There are now 24 rabbits.

It looks like you neglected to count the rabbits from the initial conditions for the second generation.

[Mr. Robin Parsons]

The answer is six. After the first generation, they can't mate anymore because that goes against incest laws.
Here's how it really works:
Year 1:
Two rabbits mate. Eight rabbits are now around.
Year 2:
All four pairs mate (including the first pair), creating 16 more rabbits. There are now 24 rabbits.
It looks like you neglected to count the rabbits from the initial conditions for the second generation.
If you start with two, (One male and ONE female) they mate, resulting in four (2M 2F) new births, how do you arrive at Eight rabbits?

[Mr. Robin Parsons]

© Mr. Robin Parsons :cool: Kingston Ontario Canada MMVI

Officeshredder

It goes like this...
-----------------

My Professor gave me an assignment, to ascertain the answer to 2 + 2

I have obtained an answer of 4 But my Answer key tells me that 4 is not the right answer.

Can you help?

----------------

Btw Officeshredder that is what you are 'guilty' of, Having been "willing to help"

That's Not 'wrong'.

You learn two other things two, the Poster is a Prankster, and that prank.

[Mr. Robin Parsons]

officeshredder,the-space-bar-on-this-computer-no-longer-works,-so-forgive-me,go-read-this-threadpost/sameposter (http://physicsmathforums.com/showthread.php?t=556
)/gives-it-away-with-"answer-key-doesn't-know-right-answer"

[QUOTE=desibaba]I have a question that I have been having some trouble with:

A cubical wooden block with an edge length of 10 cm contains a cubical hollow space with a 4 cm edge inside. What is the volume of wood making up the block ?

My answer was 936 cm^3; however the answer key says I am wrong (it doesn't tell me the "correct" answer)

I would appreciate your helpshows-the-illogic-in-that-absence-of-all-potential-answers-from-the-"answer-key"which-is-not-therefore-an-"answer-key"-but-a-computational-compounder-confounder

yes-really-the-space-bar-isn't-working

does-that-help?