GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 16 Oct 2018, 09:35

### 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

# Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 49915
Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million  [#permalink]

### Show Tags

16 Jun 2018, 00:20
00:00

Difficulty:

25% (medium)

Question Stats:

76% (01:31) correct 24% (01:22) wrong based on 88 sessions

### HideShow timer Statistics

Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million has a particular mutation. Approximately how many of the bacteria have the mutation?

(A) 7
(B) 73
(C) 733
(D) 7,333
(E) 73,333

_________________
Manager
Joined: 24 Jun 2013
Posts: 99
Re: Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million  [#permalink]

### Show Tags

16 Jun 2018, 01:44
Bunuel wrote:
Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million has a particular mutation. Approximately how many of the bacteria have the mutation?

(A) 7
(B) 73
(C) 733
(D) 7,333
(E) 73,333

we just need to find how many 75 million (1million = $$10^6$$) make 5.5 billion (1billion = $$10^9$$)

$$\frac{5.5*10^9}{75*10^6}$$
~73
Ans B
_________________

If this post helped you learn something pls give kudos

Intern
Joined: 31 Jan 2017
Posts: 9
Re: Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million  [#permalink]

### Show Tags

16 Jun 2018, 12:41
I did it the long way:

5,500,000,000 * (1/75,000,000) --> 5,500 * (1/75) --> (5,500/75) --> (1100/15) --> (220/3) --> 73.~

Intern
Joined: 26 Jul 2017
Posts: 6
Re: Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million  [#permalink]

### Show Tags

16 Jun 2018, 12:55
B

5.5bn = 5500m

75m has 1 mutation
5500m has 5500/75 = 73.33
Manager
Joined: 31 Aug 2016
Posts: 140
Location: India
Concentration: Finance, General Management
GMAT 1: 680 Q49 V33
GPA: 2.81
Re: Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 millio  [#permalink]

### Show Tags

05 Jul 2018, 08:35
Bunuel wrote:
Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 million has a particular mutation. Approximately how many of these bacteria have the mutation?

(A) 7
(B) 73
(C) 733
(D) 7,333
(E) 73,333

1 billion = 1000 million
5.5 billion = 5500 million
$$\frac{5500}{75}$$ = 73.333

therefore answer is 73 option B
_________________

Resources
GMATNinja Webinars
GMATNinja Chats

Quant
Mixtures

Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4096
Location: India
GPA: 3.5
Re: Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 millio  [#permalink]

### Show Tags

05 Jul 2018, 11:04
Bunuel wrote:
Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 million has a particular mutation. Approximately how many of these bacteria have the mutation?

(A) 7
(B) 73
(C) 733
(D) 7,333
(E) 73,333

$$75$$ million has $$1$$ bacterial mutation
$$1$$ million has $$\frac{1}{75}$$ bacterial mutations
$$5500$$ million has $$\frac{1}{75}*5500$$ bacteria $$~$$ $$73$$ bacterial mutations , Answer must be (B)
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

Director
Status: Learning stage
Joined: 01 Oct 2017
Posts: 891
WE: Supply Chain Management (Energy and Utilities)
Re: Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 millio  [#permalink]

### Show Tags

05 Jul 2018, 12:47
Bunuel wrote:
Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 million has a particular mutation. Approximately how many of these bacteria have the mutation?

(A) 7
(B) 73
(C) 733
(D) 7,333
(E) 73,333

Total no of bacteria having mutation=Total no of bacteria* rate of mutation=5.5 billion*$$\frac{1 nos}{75 million}$$=$$\frac{5.5*1000 million}{75million}$$=73(Approx.)
Ans. (B)
_________________

Regards,

PKN

Rise above the storm, you will find the sunshine

e-GMAT Representative
Joined: 04 Jan 2015
Posts: 2063
Re: Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 millio  [#permalink]

### Show Tags

06 Jul 2018, 02:39

Solution

Given:
• Total number of bacteria grown for an experiment = 5.5 billion
• 1 in every 75 million bacteria has a particular mutation

To find:
• Approximately, how many of these 5.5 billion bacteria has the mutation

Approach and Working:
• In 75 million bacteria, there is 1 bacteria with the mutation
• In 5.5 billion bacteria grown for the experiment, number of bacteria which have the mutation = 1 * 5.5 billion/75 million = (5.5 * $$10^9$$)/(75 * $$10^6$$) = 5500/75
• The value is greater than 10 and less than 100

Hence, the correct answer is option B.

_________________

Number Properties | Algebra |Quant Workshop

Success Stories
Guillermo's Success Story | Carrie's Success Story

Ace GMAT quant
Articles and Question to reach Q51 | Question of the week

Number Properties – Even Odd | LCM GCD | Statistics-1 | Statistics-2
Word Problems – Percentage 1 | Percentage 2 | Time and Work 1 | Time and Work 2 | Time, Speed and Distance 1 | Time, Speed and Distance 2
Advanced Topics- Permutation and Combination 1 | Permutation and Combination 2 | Permutation and Combination 3 | Probability
Geometry- Triangles 1 | Triangles 2 | Triangles 3 | Common Mistakes in Geometry
Algebra- Wavy line | Inequalities

Practice Questions
Number Properties 1 | Number Properties 2 | Algebra 1 | Geometry | Prime Numbers | Absolute value equations | Sets

| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

Senior Manager
Joined: 06 Jan 2015
Posts: 485
Location: India
Concentration: Operations, Finance
GPA: 3.35
WE: Information Technology (Computer Software)
Re: Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 millio  [#permalink]

### Show Tags

07 Jul 2018, 03:50
1
Bunuel wrote:
Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 million has a particular mutation. Approximately how many of these bacteria have the mutation?

(A) 7
(B) 73
(C) 733
(D) 7,333
(E) 73,333

HI Bunuel ,

Is OA E? Can you please correct it?
_________________

आत्मनॊ मोक्षार्थम् जगद्धिताय च

Resource: GMATPrep RCs With Solution

Math Expert
Joined: 02 Sep 2009
Posts: 49915
Re: Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million  [#permalink]

### Show Tags

07 Jul 2018, 07:42
NandishSS wrote:
Bunuel wrote:
Out of 5.5 billion of bacteria grown for an experiment, 1 in 75 million has a particular mutation. Approximately how many of these bacteria have the mutation?

(A) 7
(B) 73
(C) 733
(D) 7,333
(E) 73,333

HI Bunuel ,

Is OA E? Can you please correct it?

The OA is B. Edited. Thank you.
_________________
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 3824
Location: United States (CA)
Re: Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million  [#permalink]

### Show Tags

07 Jul 2018, 18:26
Bunuel wrote:
Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million has a particular mutation. Approximately how many of the bacteria have the mutation?

(A) 7
(B) 73
(C) 733
(D) 7,333
(E) 73,333

We can create the proportion:

5,500,000,000/n = 75,000,000/1

n = 5,500,000,000/75,000,000 = 5500/75 = about 73

_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Manager
Joined: 19 Nov 2017
Posts: 152
Location: India
Schools: ISB
GMAT 1: 670 Q49 V32
GPA: 4
Re: Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million  [#permalink]

### Show Tags

07 Jul 2018, 23:34
$$2^0$$ in 75 million
$$2^1$$ in 150 million (number of bacteria with a mutation doubles every time the sample is doubled i.e 75-150-300-..)
$$2^2$$ in 300 million
$$2^3$$ in 600 million
$$2^4$$ in 1200 million
$$2^5$$ in 2400 million
$$2^6$$ in 4800 million; $$2^6 = 64$$
$$2^7$$ in 9600 million;$$2^7 = 128$$

An option between 64 and 128. Answer is B, 73.
_________________

Regards,

Vaibhav

Sky is the limit. 800 is the limit.

~GMAC

Re: Out of 5.5 billion bacteria grown for an experiment, 1 in 75 million &nbs [#permalink] 07 Jul 2018, 23:34
Display posts from previous: Sort by