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# A certain population of bacteria doubles every 10 minutes.

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Math Expert
Joined: 02 Sep 2009
Posts: 64174
A certain population of bacteria doubles every 10 minutes.  [#permalink]

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05 Jan 2014, 12:05
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20
00:00

Difficulty:

5% (low)

Question Stats:

83% (01:11) correct 17% (01:12) wrong based on 856 sessions

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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.

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Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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06 Jan 2014, 07:48
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Bunuel wrote:
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)
##### General Discussion
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Joined: 02 Sep 2009
Posts: 64174
Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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05 Jan 2014, 12:06
1
RESERVED FOR A SOLUTION.
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Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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05 Jan 2014, 19:50
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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
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Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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05 Jan 2014, 20:22
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)
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Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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29 Jul 2016, 11:53
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
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Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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16 Jul 2017, 01:05
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 wrote:
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:
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!

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Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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17 Jul 2017, 10:03
Bunuel wrote:
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:
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!

=====

(10^4)
After 10 mins, 2*(10^4)
After 20 mins, 2*(2*(10^4))
After 10 mins,
Bunuel wrote:
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:
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!

=====

(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

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Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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15 Sep 2019, 04:54
1
Bunuel wrote:
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:
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!

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
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Re: A certain population of bacteria doubles every 10 minutes.  [#permalink]

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19 Dec 2019, 06:35
1
Top Contributor
1
Bunuel wrote:
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

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)

Cheers,
Brent
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Re: A certain population of bacteria doubles every 10 minutes.   [#permalink] 19 Dec 2019, 06:35