Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 03 May 2016, 09:49

GMAT Club Daily Prep

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

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Growth

Author Message
Manager
Joined: 04 Dec 2008
Posts: 104
Followers: 2

Kudos [?]: 120 [0], given: 2

Show Tags

16 Jul 2009, 02:41
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statictics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

The population of a bacteria culture doubles every 2 minutes. Approximately how many minutes will it take for the population to grow from 1,000 to 500,000 bacteria?

(A) 10
(B) 12
(C) 14
(D) 16
(E) 18

Is there a shortcut to growth questions? Thks.
Senior Manager
Joined: 23 Jun 2009
Posts: 353
Location: Turkey
Schools: UPenn, UMich, HKS, UCB, Chicago
Followers: 5

Kudos [?]: 116 [0], given: 63

Show Tags

16 Jul 2009, 03:26
in min1=x becomes 2x
in min2= 2x becomes 4x
....
in minn=x.$$2^(n-1)$$ becomes x.$$2^n$$
x.$$2^n$$ / x = $$2^n$$
When we take the logarithmics of right side in base 2
log2($$2^n$$) we can find n
That is maths.
But in this question we can an easy approach.
500000/1000=500
it is greater than 256 (2^8) and it is less than 512 (2^9) so we can say that in 9 minutes bacteria can grow up to that size.
Senior Manager
Joined: 23 Jun 2009
Posts: 353
Location: Turkey
Schools: UPenn, UMich, HKS, UCB, Chicago
Followers: 5

Kudos [?]: 116 [0], given: 63

Show Tags

16 Jul 2009, 12:58
Thanks walker 9x2 = 18 minutes
Re: Growth   [#permalink] 16 Jul 2009, 12:58
Display posts from previous: Sort by