Last visit was: 18 Nov 2025, 15:48 It is currently 18 Nov 2025, 15:48
Home
GMAT
Messages
Tests
Schools
Events
Rewards
Chat
My Profile
Close
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
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
Sub 505 Level|   Algebra|                           
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 18 Nov 2025
Posts: 105,355
Own Kudos:
778,068
 [56]
Given Kudos: 99,964
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,355
Kudos: 778,068
 [56]
A certain population of bacteria doubles every 10 minutes. If the 05 Jan 2014, 13:05
7
Kudos
Add Kudos
49
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

5% (low)

Question Stats:

84% (01:09) correct 16% (01:14) wrong based on 2244 sessions

History

Date
Time
Result
Not Attempted Yet
A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6
ShowHide Answer
Official Answer
C
Most Helpful Reply
User avatar
BrentGMATPrepNow
User avatar
Major Poster
Joined: 12 Sep 2015
Last visit: 31 Oct 2025
Posts: 6,739
Own Kudos:
35,331
 [13]
Given Kudos: 799
Location: Canada
Expert
Expert reply
Posts: 6,739
Kudos: 35,331
 [13]
A certain population of bacteria doubles every 10 minutes. If the 19 Dec 2019, 07:35
9
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND Edition

A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6
Show more

Let's list some populations and look for a pattern

Initial population: 10⁴
10 minutes later: (10⁴)(2)
20 minutes later: (10⁴)(2)(2)
30 minutes later: (10⁴)(2)(2)(2)
40 minutes later: (10⁴)(2)(2)(2)(2)
50 minutes later: (10⁴)(2)(2)(2)(2)(2)
60 minutes later: (10⁴)(2)(2)(2)(2)(2)(2) = (10⁴)(2⁶)

Answer: C

Cheers,
Brent
User avatar
kinjiGC
User avatar
Joined: 03 Feb 2013
Last visit: 12 Oct 2025
Posts: 791
Own Kudos:
2,717
 [13]
Given Kudos: 567
Location: India
Concentration: Operations, Strategy
Schools: Tepper '17 (M$) W.P. Carey '17 (A$) NUS '17 (A)
GMAT 1: 760 Q49 V44
GPA: 3.88
WE:Engineering (Computer Software)
Products:
My Reviews
Schools: Tepper '17 (M$) W.P. Carey '17 (A$) NUS '17 (A)
GMAT 1: 760 Q49 V44
Posts: 791
Kudos: 2,717
 [13]
A certain population of bacteria doubles every 10 minutes. If the 06 Jan 2014, 08:48
8
Kudos
Add Kudos
5
Bookmarks
Bookmark this Post
Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND Edition

A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6

Show more

Difficulty level : sub 500.

Starting population, 10^4
After 10 mins , the population becomes 2^1* 10^4
After 20 mins , the population becomes 2^2* 10^4
So after 1 hour (which is 60 mins), the population becomes 2^6 * 10^4 - option c)
General Discussion
User avatar
WoundedTiger
User avatar
Joined: 25 Apr 2012
Last visit: 25 Sep 2024
Posts: 521
Own Kudos:
2,534
 [8]
Given Kudos: 740
Location: India
GPA: 3.21
WE:Business Development (Other)
Products:
My Reviews
Posts: 521
Kudos: 2,534
 [8]
A certain population of bacteria doubles every 10 minutes. If the 05 Jan 2014, 20:50
3
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6

Sol: We need to find the population of the bacteria 1 hour later. Let Initial Population be x =10^4
After 10 mins: 2x
20 mins: 4x
30 mins: 8x
40 mins: 16x
50 mins: 32x
60 mins: 64 x--------> 2^6*x -----> 2^6*10^4. Ans C
User avatar
nutshell
User avatar
Joined: 21 Mar 2011
Last visit: 04 Jul 2019
Posts: 95
Own Kudos:
298
Given Kudos: 104
Status:GMATting
Concentration: Strategy, Technology
GMAT 1: 590 Q45 V27
GMAT 1: 590 Q45 V27
Posts: 95
Kudos: 298
A certain population of bacteria doubles every 10 minutes. If the 05 Jan 2014, 21:22
Kudos
Add Kudos
Bookmarks
Bookmark this Post
An hour has 6 10-min intervals. If the population of bacteria doubles(2x) every 10 mins, then in 1 hour it will have multiplied by 2^6 times.

So, after 1 hour it will be (2^6)(10^4).

Ans is (C)
User avatar
stonecold
User avatar
Joined: 12 Aug 2015
Last visit: 09 Apr 2024
Posts: 2,244
Own Kudos:
3,549
 [1]
Given Kudos: 893
Schools: Boston U '20 (M)
GRE 1: Q169 V154
Schools: Boston U '20 (M)
GRE 1: Q169 V154
Posts: 2,244
Kudos: 3,549
 [1]
A certain population of bacteria doubles every 10 minutes. If the 29 Jul 2016, 12:53
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Let us solve this using the GP extension
Here R i.e the common multiple =2
after 60 minutes => 7th term => 2^6*64
Smash that C
User avatar
susheelh
User avatar
Joined: 12 Jun 2016
Last visit: 13 Jun 2018
Posts: 144
Own Kudos:
287
Given Kudos: 151
Location: India
Concentration: Technology, Leadership
WE:Sales (Telecommunications)
Posts: 144
Kudos: 287
A certain population of bacteria doubles every 10 minutes. If the 16 Jul 2017, 02:05
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello Moderators,

Do you think the answers choices need to be made math Friendly? On a quick look, Option B and Option E "look" the same (Which of course is not the case). This ambiguity can be removed if answer choices are made math friendly.


Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND Edition

A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6

Problem Solving
Question: 22
Category: Arithmetic Operations on rational numbers
Page: 64
Difficulty: 600

GMAT Club is introducing a new project: The Official Guide For GMAT® Quantitative Review, 2ND Edition - Quantitative Questions Project

Each week we'll be posting several questions from The Official Guide For GMAT® Quantitative Review, 2ND Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.

We'll be glad if you participate in development of this project:
1. Please provide your solutions to the questions;
2. Please vote for the best solutions by pressing Kudos button;
3. Please vote for the questions themselves by pressing Kudos button;
4. Please share your views on difficulty level of the questions, so that we have most precise evaluation.

Thank you!
Show more
User avatar
Inten21
User avatar
Joined: 18 Jan 2017
Last visit: 06 Sep 2022
Posts: 123
Own Kudos:
98
 [1]
Given Kudos: 155
Posts: 123
Kudos: 98
 [1]
A certain population of bacteria doubles every 10 minutes. If the 17 Jul 2017, 11:03
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND Edition

A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6

Problem Solving
Question: 22
Category: Arithmetic Operations on rational numbers
Page: 64
Difficulty: 600

GMAT Club is introducing a new project: The Official Guide For GMAT® Quantitative Review, 2ND Edition - Quantitative Questions Project

Each week we'll be posting several questions from The Official Guide For GMAT® Quantitative Review, 2ND Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.

We'll be glad if you participate in development of this project:
1. Please provide your solutions to the questions;
2. Please vote for the best solutions by pressing Kudos button;
3. Please vote for the questions themselves by pressing Kudos button;
4. Please share your views on difficulty level of the questions, so that we have most precise evaluation.

Thank you!
Show more




ANSWER:
=====

(10^4)
After 10 mins, 2*(10^4)
After 20 mins, 2*(2*(10^4))
After 10 mins,
Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND Edition

A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6

Problem Solving
Question: 22
Category: Arithmetic Operations on rational numbers
Page: 64
Difficulty: 600

GMAT Club is introducing a new project: The Official Guide For GMAT® Quantitative Review, 2ND Edition - Quantitative Questions Project

Each week we'll be posting several questions from The Official Guide For GMAT® Quantitative Review, 2ND Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.

We'll be glad if you participate in development of this project:
1. Please provide your solutions to the questions;
2. Please vote for the best solutions by pressing Kudos button;
3. Please vote for the questions themselves by pressing Kudos button;
4. Please share your views on difficulty level of the questions, so that we have most precise evaluation.

Thank you!
Show more




ANSWER:
=====

(10^4)
After 10 mins, 2*(10^4)
After 20 mins, 2*2*(10^4)
After 30 mins, 2*2*2*(10^4))
After 40 mins, 2*2*2*2*(10^4)
After 50 mins, 2*2*2*2*2*(10^4)
After 60 mins, 2*2*2*2*2*2*(10^4)

2^6 * (10^4)


Hence, Answer is (2^6)(10^4) = C
User avatar
Kinshook
User avatar
Major Poster
Joined: 03 Jun 2019
Last visit: 18 Nov 2025
Posts: 5,793
Own Kudos:
5,508
 [1]
Given Kudos: 161
Location: India
Schools: HBS '26 CBS '26 Wharton '26
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Products:
My Reviews
Schools: HBS '26 CBS '26 Wharton '26
GMAT 1: 690 Q50 V34
Posts: 5,793
Kudos: 5,508
 [1]
A certain population of bacteria doubles every 10 minutes. If the 15 Sep 2019, 05:54
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND Edition

A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6

Problem Solving
Question: 22
Category: Arithmetic Operations on rational numbers
Page: 64
Difficulty: 600

GMAT Club is introducing a new project: The Official Guide For GMAT® Quantitative Review, 2ND Edition - Quantitative Questions Project

Each week we'll be posting several questions from The Official Guide For GMAT® Quantitative Review, 2ND Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.

We'll be glad if you participate in development of this project:
1. Please provide your solutions to the questions;
2. Please vote for the best solutions by pressing Kudos button;
3. Please vote for the questions themselves by pressing Kudos button;
4. Please share your views on difficulty level of the questions, so that we have most precise evaluation.

Thank you!
Show more


Every 10 minutes population of bacteria = 2 times
Every 60 minutes population of bacteria becomes = 2*2*2*2*2*2= 2^6 times

Since initially population of bacteria = 10^4

Population of bacteria after 1 hour ( 60 minutes) =( 2^6) * (10^4)

IMO C

Posted from my mobile device
User avatar
Karanzzz11
User avatar
Joined: 27 Dec 2024
Last visit: 12 Nov 2025
Posts: 8
Own Kudos:
5
Given Kudos: 1
Location: India
Concentration: General Management, Marketing
GPA: 7.5
WE:Account Management (Advertising and PR)
Posts: 8
Kudos: 5
A certain population of bacteria doubles every 10 minutes. If the 11 Aug 2025, 04:42
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Could you explain it once again please in another manner.
kinjiGC
Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND Edition

A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6


Difficulty level : sub 500.

Starting population, 10^4
After 10 mins , the population becomes 2^1* 10^4
After 20 mins , the population becomes 2^2* 10^4
So after 1 hour (which is 60 mins), the population becomes 2^6 * 10^4 - option c)
Show more
User avatar
Krunaal
User avatar
Tuck School Moderator
Joined: 15 Feb 2021
Last visit: 17 Nov 2025
Posts: 805
Own Kudos:
850
 [1]
Given Kudos: 251
Status:Under the Square and Compass
Location: India
Schools: Booth '26 Kellogg '26 Johnson '26 Tuck '26 Duke '26 Ross '26 HBS '26 Stanford '26 CBS '26 Stern '26 Kellogg Darden '26 Yale '26 Wharton '26
GMAT Focus 1: 755 Q90 V90 DI82
GPA: 5.78
WE:Marketing (Consulting)
Products:
My Reviews
Schools: Booth '26 Kellogg '26 Johnson '26 Tuck '26 Duke '26 Ross '26 HBS '26 Stanford '26 CBS '26 Stern '26 Kellogg Darden '26 Yale '26 Wharton '26
GMAT Focus 1: 755 Q90 V90 DI82
Posts: 805
Kudos: 850
 [1]
A certain population of bacteria doubles every 10 minutes. If the Updated on: 11 Aug 2025, 05:14
Originally posted by Krunaal on 11 Aug 2025, 05:13.
Last edited by Krunaal on 11 Aug 2025, 05:14, edited 2 times in total.
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Karanzzz11
Could you explain it once again please in another manner.
kinjiGC
Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND Edition

A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^4, what was the number in the population 1 hour later?

(A) 2(10^4)
(B) 6(10^4)
(C) (2^6)(10^4)
(D) (10^6)(10^4)
(E) (10^4)^6


Difficulty level : sub 500.

Starting population, 10^4
After 10 mins , the population becomes 2^1* 10^4
After 20 mins , the population becomes 2^2* 10^4
So after 1 hour (which is 60 mins), the population becomes 2^6 * 10^4 - option c)
Show more
Every 10 mins the population doubles, i.e. it gets 2x every 10 mins.

So if it is \(10^4\) in beginning, it will be \(2*10^4\) after 10 mins. After 10 more mins, i.e. after 20 mins from start, it will be \(2*2*10^4\). Similarly, after 60 mins from start, it will be \(2*2*2*2*2*2*10^4\) => \(2^6*10^4\)
Moderators:
Bunuel
Math Expert
105355 posts
Krunaal
Tuck School Moderator
805 posts