Population of Town

This topic has expert replies
User avatar
Legendary Member
Posts: 1132
Joined: Mon Jul 20, 2009 3:38 am
Location: India
Thanked: 64 times
Followed by:6 members
GMAT Score:760

Population of Town

by harsh.champ » Wed Feb 17, 2010 4:05 am
The population of a town doubles every 5 years.If the population at the end of 2000 was 320000,what was it at the beginning of 1961?

(A)1250
(B)80000
(C)12500
(D)12000
(E)16000
It takes time and effort to explain, so if my comment helped you please press Thanks button :)



Just because something is hard doesn't mean you shouldn't try,it means you should just try harder.

"Keep Walking" - Johnny Walker :P
Source: — Problem Solving |

User avatar
Legendary Member
Posts: 1275
Joined: Thu Sep 21, 2006 11:13 pm
Location: Arabian Sea
Thanked: 125 times
Followed by:2 members

by ajith » Wed Feb 17, 2010 4:26 am
harsh.champ wrote:The population of a town doubles every 5 years.If the population at the end of 2000 was 320000,what was it at the beginning of 1961?

(A)1250
(B)80000
(C)12500
(D)12000
(E)16000
In 40 years population must have grown 2^(40/5) = 2^8 = 256times
Population at the end of 2000 = 320000
Population at the start of 1961 =320000/256 =1250, A
Always borrow money from a pessimist, he doesn't expect to be paid back.

User avatar
Legendary Member
Posts: 1022
Joined: Mon Jul 20, 2009 11:49 pm
Location: Gandhinagar
Thanked: 41 times
Followed by:2 members

by shashank.ism » Wed Feb 17, 2010 9:38 am
harsh.champ wrote:The population of a town doubles every 5 years.If the population at the end of 2000 was 320000,what was it at the beginning of 1961?

(A)1250
(B)80000
(C)12500
(D)12000
(E)16000

At the beginning of 1961 means end of 1960 ...
so from end of 1960 to end of 2000 = 40 years
since population doubles every 5 years... so P = 320000/2^(40/5) = 320000/2^8 = 320000/(32x2x2x2) = 10000/8 =1250 Ans A
My Websites:
www.mba.webmaggu.com - India's social Network for MBA Aspirants

www.deal.webmaggu.com -India's online discount, coupon, free stuff informer.

www.dictionary.webmaggu.com - A compact free online dictionary with images.

Nothing is Impossible, even Impossible says I'm possible.

User avatar
Legendary Member
Posts: 2109
Joined: Sun Apr 19, 2009 10:25 pm
Location: New Jersey
Thanked: 109 times
Followed by:79 members
GMAT Score:640

by money9111 » Wed Feb 17, 2010 9:49 am
here's another case of Harsh.Champ starting the post and Shashank.ism finishing it... i repeat... very curious...
My goal is to make MBA applicants take onus over their process.

My story from Pre-MBA to Cornell MBA - New Post in Pre-MBA blog

Me featured on Poets & Quants

Free Book for MBA Applicants


User avatar
Legendary Member
Posts: 1022
Joined: Mon Jul 20, 2009 11:49 pm
Location: Gandhinagar
Thanked: 41 times
Followed by:2 members

by shashank.ism » Wed Feb 17, 2010 9:58 am
money9111 wrote:here's another case of Harsh.Champ starting the post and Shashank.ism finishing it... i repeat... very curious...
I think money1119 is the last one again appraising or commenting whatever as usual, he comes and creates a comment out of anything..its interesting.
though the first time i pointed it out here..
My Websites:
www.mba.webmaggu.com - India's social Network for MBA Aspirants

www.deal.webmaggu.com -India's online discount, coupon, free stuff informer.

www.dictionary.webmaggu.com - A compact free online dictionary with images.

Nothing is Impossible, even Impossible says I'm possible.