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A certain population of bacteria doubles every 10 minutes.
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05 Jan 2014, 13:05
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The Official Guide For GMAT® Quantitative Review, 2ND EditionA 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 ProjectEach 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!
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Re: A certain population of bacteria doubles every 10 minutes.
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05 Jan 2014, 13:06



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Re: A certain population of bacteria doubles every 10 minutes.
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05 Jan 2014, 20:50
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)^6Sol: 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.
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05 Jan 2014, 21:22
An hour has 6 10min 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.
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06 Jan 2014, 08:48
Bunuel wrote: The Official Guide For GMAT® Quantitative Review, 2ND EditionA 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)
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Re: A certain population of bacteria doubles every 10 minutes.
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29 Jul 2016, 12:53



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Re: A certain population of bacteria doubles every 10 minutes.
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16 Jul 2017, 02:05
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 EditionA 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 ProjectEach 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!
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Re: A certain population of bacteria doubles every 10 minutes.
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17 Jul 2017, 11:03
Bunuel wrote: The Official Guide For GMAT® Quantitative Review, 2ND EditionA 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 ProjectEach 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! ANSWER: ===== (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 EditionA 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 ProjectEach 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! 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
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Re: A certain population of bacteria doubles every 10 minutes.
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29 Aug 2018, 03:51
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