GMAT Changed on April 16th - Read about the latest changes here

It is currently 22 Apr 2018, 22:27

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Data for a certain biology experiment are given in the table

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

1 KUDOS received
BSchool Forum Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 2436
Location: India
GPA: 3.12
Premium Member CAT Tests
Re: Data for a certain biology experiment are given in the table [#permalink]

Show Tags

New post 04 Apr 2018, 06:36
1
This post received
KUDOS
1
This post was
BOOKMARKED
dave13 wrote:
AKProdigy87 wrote:
Let X represent the amount of bacteria present at 4:00 PM. Since the fractional increase must remain constant from 1 to 4pm as it is from 4pm to 7pm:

Fractional increase from 1 PM to 4 PM = X / 10.0
Fractional increase from 4 PM to 7 PM = 14.4 / X

\(\frac{X}{10.0} = \frac{14.4}{X}\)

\(X^2 = (14.4)(10.0)\)

\(X^2 = 144\)

\(X = 12\)

Therefore, the correct answer is A: 12.0.


Hi pushpitkc

can you please explain why

here x is numerator Fractional increase from 1 PM to 4 PM = X / 10.0 ?

and here x is in denominator Fractional increase from 4 PM to 7 PM = 14.4 / X ?

many thanks!


Hey dave13

The answer to your question lies in the question stem
1:00 P.M. 10.0 grams
4:00 P.M. x grams
7:00 P.M. 14.4 grams

It is given that the bacteria increased by the same fraction during each of the two 3-hour periods

The increase in bacteria in the first three hour period = Bacteria(4 PM)/Bacterial(1 PM) = x/10
The increase in bacteria in the second three hour period = Bacteria(7 PM)/Bacterial(4 PM) = 14.4/x

Hope this helps you!
_________________

Stay hungry, Stay foolish

2017-2018 MBA Deadlines

Class of 2020: Rotman Thread | Schulich Thread
Class of 2019: Sauder Thread

Expert Post
Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2273
Re: Data for a certain biology experiment are given in the table [#permalink]

Show Tags

New post 06 Apr 2018, 08:45
tejal777 wrote:
AMOUNT OF BACTERIA PRESENT
Time Amount
1:00 P.M. 10.0 grams
4:00 P.M. x grams
7:00 P.M. 14.4 grams

Data for a certain biology experiment are given in the table above. If the amount of bacteria present increased by the same fraction during each of the two 3-hour periods shown, how many grams of bacteria were present at 4:00 P.M.?

A. 12.0
B. 12.1
C. 12.2
D. 12.3
E. 12.4



We can let n = the multiplier for each 3-hour period. So, we have:

1 p.m. = 10 grams

4 p.m. = 10n

7 p.m. = 10n^2

We can create the following equation:

10n^2 = 14.4

n^2 = 1.44

n = 1.2

Thus, we have 10n = 10(1.2) = 12 grams of bacteria at 4 p.m.

Alternate Solution:

Since the fractional increase is the same for both 3-hour periods, we must have:

x/10 = 14.4/x

x^2 = 144

x = 12 or x = -12

Since the number of bacteria cannot be negative, the answer is 12.

Answer: A
_________________

Jeffery Miller
Head of GMAT Instruction

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

Re: Data for a certain biology experiment are given in the table   [#permalink] 06 Apr 2018, 08:45

Go to page   Previous    1   2   [ 22 posts ] 

Display posts from previous: Sort by

Data for a certain biology experiment are given in the table

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.