Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

A certain rabbit population quadruples every three years. [#permalink]
11 Dec 2012, 22:06

3

This post received KUDOS

1

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

(N/A)

Question Stats:

100% (01:45) correct
0% (00:00) wrong based on 57 sessions

Going to have a go at Problem Solving.. My own question, so no official answer. Please provide your feedback on how you found the question to be and anyway that I can make it clearer..

A certain rabbit population quadruples every three years. The population today is 81. Exactly six years from today, the entire population will be fed to a pack of wolves. If each wolf eats exactly 12 rabbits, how many wolves can be fed using this rabbit population?

Re: A certain rabbit population quadruples every three years. [#permalink]
11 Dec 2012, 22:47

Expert's post

MacFauz wrote:

Going to have a go at Problem Solving.. My own question, so no official answer. Please provide your feedback on how you found the question to be and anyway that I can make it clearer..

A certain rabbit population quadruples every three years. The population today is 81. Exactly six years from today, the entire population will be fed to a pack of wolves. If each wolf eats exactly 12 rabbits, how many wolves can be fed using this rabbit population?

\(y(t)=y(0) * 4^[t/I]\) where: y(t)=population after given number of years. y(0)=initial population t=time I=amount of the time for the quantity to double. Putting the respective values, we get population after 6 years as 1296. Divide this by the exact capacity of wolves, and we get 108 as the answer.

Logical method: the population is quadrupling two times. So find the population as soon as it quadruples for the first time. Then multiply the result again by 4 to get the population after 6 years. And then the same.

+1C.

Btw Macfauz, you may apply to GMAC. I am quite certain that within a year or two, you may be writing questions for future GMAT takers. Good Luck. _________________

Re: A certain rabbit population quadruples every three years. [#permalink]
11 Dec 2012, 22:58

Marcab wrote:

MacFauz wrote:

Going to have a go at Problem Solving.. My own question, so no official answer. Please provide your feedback on how you found the question to be and anyway that I can make it clearer..

A certain rabbit population quadruples every three years. The population today is 81. Exactly six years from today, the entire population will be fed to a pack of wolves. If each wolf eats exactly 12 rabbits, how many wolves can be fed using this rabbit population?

\(y(t)=y(0) * 4^[t/I]\) where: y(t)=population after given number of years. y(0)=initial population t=time I=amount of the time for the quantity to double. Putting the respective values, we get population after 6 years as 1296. Divide this by the exact capacity of wolves, and we get 108 as the answer.

Logical method: the population is quadrupling two times. So find the population as soon as it quadruples for the first time. Then multiply the result again by 4 to get the population after 6 years. And then the same.

+1C.

Btw Macfauz, you may apply to GMAC. I am quite certain that within a year or two, you may be writing questions for future GMAT takers. Good Luck.

Haha.. Thanks Marcab.. Hopefully will be able to come up with more questions here before I can do that..

Btw.. For the question.. We can save some time on the multiplication by keeping the final population in the form

\(3^4 * 2^4\). Dividing this by 12 we get : \(\frac{3^4 * 2^4}{2^2 * 3}\) = \(3^3 * 2^2\) = 108 _________________

Did you find this post helpful?... Please let me know through the Kudos button.

Re: A certain rabbit population quadruples every three years. [#permalink]
10 Jan 2013, 19:08

Marcab wrote:

MacFauz wrote:

Going to have a go at Problem Solving.. My own question, so no official answer. Please provide your feedback on how you found the question to be and anyway that I can make it clearer..

A certain rabbit population quadruples every three years. The population today is 81. Exactly six years from today, the entire population will be fed to a pack of wolves. If each wolf eats exactly 12 rabbits, how many wolves can be fed using this rabbit population?

\(y(t)=y(0) * 4^[t/I]\) where: y(t)=population after given number of years. y(0)=initial population t=time I=amount of the time for the quantity to double. Putting the respective values, we get population after 6 years as 1296. Divide this by the exact capacity of wolves, and we get 108 as the answer.

Logical method: the population is quadrupling two times. So find the population as soon as it quadruples for the first time. Then multiply the result again by 4 to get the population after 6 years. And then the same.

+1C.

Btw Macfauz, you may apply to GMAC. I am quite certain that within a year or two, you may be writing questions for future GMAT takers. Good Luck.

Hi Marcab,

I solved this using logical method. But i tried to figure out ur algebraic method ... i couldn't

y(t)=population after given number of years. (x) y(0)=initial population (81) t=time (6) I=amount of the time for the quantity to double. (3)

i'm getting x= 81*2 _________________

GMAT - Practice, Patience, Persistence Kudos if u like

Re: A certain rabbit population quadruples every three years. [#permalink]
10 Jan 2013, 21:06

Expert's post

Hii Shan. If you are pretty comfortable with the logical method, then don't get confuse with this one. Anyways, here is the clarification of my method: \(y(t)=y(0)*4^{t/I}\)

where y(t)= population after 6 years. y(0)=current population=81 4- multiplying factor.( Since here its given that population is quadrupling, hence 4) t-time duration given=6 I-time interval during which the population quadruples=3

The relation becomes: \(y(t)=81*4^{6/3}\) \(y(t)=81*4^2\) \(y(t)=81*16\) or \(1296\).

On dividing this by # of rabbits, you will get the # of wolves.

Re: A certain rabbit population quadruples every three years. [#permalink]
10 Jan 2013, 23:30

Marcab wrote:

Hii Shan. If you are pretty comfortable with the logical method, then don't get confuse with this one. Anyways, here is the clarification of my method: \(y(t)=y(0)*4^{t/I}\)

where y(t)= population after 6 years. y(0)=current population=81 4- multiplying factor.( Since here its given that population is quadrupling, hence 4) t-time duration given=6 I-time interval during which the population quadruples=3

The relation becomes: \(y(t)=81*4^{6/3}\) \(y(t)=81*4^2\) \(y(t)=81*16\) or \(1296\).

On dividing this by # of rabbits, you will get the # of wolves.

Hope that helps.

Ya thanks dude.. I got this now..

But i just wanna confirm is this standard formula for these population sums? or it depends on problem ?? _________________

GMAT - Practice, Patience, Persistence Kudos if u like

Re: A certain rabbit population quadruples every three years. [#permalink]
28 Jan 2014, 13:17

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________

Re: A certain rabbit population quadruples every three years. [#permalink]
29 Jan 2014, 13:26

MacFauz wrote:

Marcab wrote:

MacFauz wrote:

Going to have a go at Problem Solving.. My own question, so no official answer. Please provide your feedback on how you found the question to be and anyway that I can make it clearer..

A certain rabbit population quadruples every three years. The population today is 81. Exactly six years from today, the entire population will be fed to a pack of wolves. If each wolf eats exactly 12 rabbits, how many wolves can be fed using this rabbit population?

\(y(t)=y(0) * 4^[t/I]\) where: y(t)=population after given number of years. y(0)=initial population t=time I=amount of the time for the quantity to double. Putting the respective values, we get population after 6 years as 1296. Divide this by the exact capacity of wolves, and we get 108 as the answer.

Logical method: the population is quadrupling two times. So find the population as soon as it quadruples for the first time. Then multiply the result again by 4 to get the population after 6 years. And then the same.

+1C.

Btw Macfauz, you may apply to GMAC. I am quite certain that within a year or two, you may be writing questions for future GMAT takers. Good Luck.

Haha.. Thanks Marcab.. Hopefully will be able to come up with more questions here before I can do that..

Btw.. For the question.. We can save some time on the multiplication by keeping the final population in the form

\(3^4 * 2^4\). Dividing this by 12 we get : \(\frac{3^4 * 2^4}{2^2 * 3}\) = \(3^3 * 2^2\) = 108

Good idea! I saw that all the answers had differing unit digits, so i just kept track of unit digit to arrive at the answer. The answer basically boils down 81* 4^6/12 i.e 27*4^5, and we know that unit digit of power of 4 alternates between 4 and 6 with unit digit of odd power of 4 being 4 , so the answer should end with 8!

Re: A certain rabbit population quadruples every three years. [#permalink]
08 Jun 2015, 14:28

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________

On September 6, 2015, I started my MBA journey at London Business School. I took some pictures on my way from the airport to school, and uploaded them on...

When I was growing up, I read a story about a piccolo player. A master orchestra conductor came to town and he decided to practice with the largest orchestra...

I’ll start off with a quote from another blog post I’ve written : “not all great communicators are great leaders, but all great leaders are great communicators.” Being...