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

It is currently 24 Mar 2019, 12:35

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

A certain kudzu plant was 11 feet long on the day it was

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

Hide Tags

 
Manager
Manager
User avatar
Joined: 23 Oct 2011
Posts: 82
A certain kudzu plant was 11 feet long on the day it was  [#permalink]

Show Tags

New post Updated on: 31 May 2013, 02:03
6
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

50% (00:00) correct 50% (02:57) wrong based on 13 sessions

HideShow timer Statistics

A certain kudzu plant was 11 feet long on the day it was planted, and the length grows by a constant amount every day (including the first day it was planted). If this plant grew 40% between the fourth day after it was planted and the tenth day after it was planted, how many feet per day does it grow?

OA:
1 foot per day


I copied a problem from ΜGMAT book that I find difficult to translate into math and would appreciate if someone had the time to walk me through. I don't want the solution to this problem. I just want someone to explain how I translate the colored sentence.

I understand its an arithmetic progression - linear growth because it says by a constant amount every day.


11 ,t=0 should I think of it as the start of the first day?
11+x , t=1 should I think of it as the start of the second day or the end of the first day?
11+2x ,t=2 .....

Should t=0 be 11+x because it said that it grew the first day that was planted?

would it be easier if I named the day it was planted as t=1?

what will the fourth day after it was planted be? t=4 or t=5?

Any thoughts?

Originally posted by SonyGmat on 17 Nov 2011, 19:20.
Last edited by Bunuel on 31 May 2013, 02:03, edited 1 time in total.
Edited the question and moved to PS forum.
Manager
Manager
User avatar
Joined: 16 Sep 2010
Posts: 189
Location: United States
Concentration: Finance, Real Estate
GMAT 1: 740 Q48 V42
Re: Linear growth Problem  [#permalink]

Show Tags

New post 17 Nov 2011, 23:41
1
Day of planting would be day 0. So fourth day after would be T=4.

You are correct on your formula of 11 + X(days) = Ending Height

Hope that helps. Let me know if you need more.
Intern
Intern
avatar
Joined: 05 Aug 2011
Posts: 18
Reviews Badge
Equations & functions  [#permalink]

Show Tags

New post 27 Nov 2011, 22:51
Hi

Need help in solving the problem

A certain plant was 11 feet long on the day it was planted & the length grows by a constant amount everyday(inc. the first day it was planted).
if this plant grew by 40% b/w the 4th day and 10 th day after it was planted ,how many feet per day does the plant grow

a) 2
b) 4.5
c) 1
d) 5.5
e) 3

Thanks
SVP
SVP
User avatar
G
Status: Top MBA Admissions Consultant
Joined: 24 Jul 2011
Posts: 1530
GMAT 1: 780 Q51 V48
GRE 1: Q800 V740
Re: Equations & functions  [#permalink]

Show Tags

New post 27 Nov 2011, 23:54
If the plant is 11 feet tall when it is planted, it will be 11 + k feet tall at the end of the day (where k is the constant length it grows by every day).

Similarly, at the end of the 4th day the plant must be 11 + 4k feet tall and at the end of the 10th day it must be 11 + 10k feet tall.

Therefore 6k = 0.4 (11 + 4k)
=> k = 1

Therefore the plant grows by 1 feet every day.

Option (C)
_________________

GyanOne | Top MBA Rankings and MBA Admissions Blog

Top MBA Admissions Consulting | Top MiM Admissions Consulting

Premium MBA Essay Review|Best MBA Interview Preparation|Exclusive GMAT coaching

Get a FREE Detailed MBA Profile Evaluation | Call us now +91 98998 31738

Intern
Intern
avatar
B
Joined: 14 Jan 2011
Posts: 36
Concentration: Finance, Strategy
GMAT 1: 610 Q46 V28
GPA: 3.53
WE: Engineering (Aerospace and Defense)
GMAT ToolKit User
Re: Linear growth Problem  [#permalink]

Show Tags

New post 30 May 2013, 14:54
I am having trouble with the wording of this problem, can someone please explain "the fourth day after it was planted"

When I worked it out I got An = (n+1)x+11 vs the solution is An = nx+11. I added an extra day because I thought it was the fourth day after the planting, and the problem also says it grows by the constant rate on the first day it was planted so A0 = 11+x, A1 = 11+2x, etc...thanks!
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 53800
Re: Linear growth Problem  [#permalink]

Show Tags

New post 31 May 2013, 02:08
2
1
penguinman wrote:
I am having trouble with the wording of this problem, can someone please explain "the fourth day after it was planted"

When I worked it out I got An = (n+1)x+11 vs the solution is An = nx+11. I added an extra day because I thought it was the fourth day after the planting, and the problem also says it grows by the constant rate on the first day it was planted so A0 = 11+x, A1 = 11+2x, etc...thanks!


A certain kudzu plant was 11 feet long on the day it was planted, and the length grows by a constant amount every day (including the first day it was planted). If this plant grew 40% between the fourth day after it was planted and the tenth day after it was planted, how many feet per day does it grow?

The length of the plant after the fourth day is \(11+4x\), where x is the growth rate per day.
The length of the plant after the tenth day is \(11+10x\).

We are given \(11+10x=1.4(11+4x)\) --> x=1 foot per day.

Hope it's clear.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Director
Director
User avatar
S
Joined: 17 Dec 2012
Posts: 626
Location: India
Re: A certain kudzu plant was 11 feet long on the day it was  [#permalink]

Show Tags

New post 31 May 2013, 02:57
1. The height on the fourth and tenth days are related with one unknown which is the growth amount. Solved by equating the two expressions
2. The plant grows by a constant amount every day. Let that be x.
3. After 4 days it would have grown by 4x
4. After 10 days it would have grown by 10x.
5. Initial height is 11 feet.
6. Height after 4 days is 11+ 4x
7. Height after 10 days is 11 + 10x
8. (6) and (7) can be related by multiplying the factor 1.4 with (6)
9. 1.4*(11+4x) = 11+10x
10 x is 1 or the the plant grows 1 foot per day
_________________

Srinivasan Vaidyaraman
Sravna Holistic Solutions
http://www.sravnatestprep.com

Holistic and Systematic Approach

Manager
Manager
avatar
Joined: 30 May 2013
Posts: 153
Location: India
Concentration: Entrepreneurship, General Management
GPA: 3.82
GMAT ToolKit User
Re: Linear growth Problem  [#permalink]

Show Tags

New post 01 Jun 2013, 22:58
Bunuel wrote:
penguinman wrote:
I am having trouble with the wording of this problem, can someone please explain "the fourth day after it was planted"

When I worked it out I got An = (n+1)x+11 vs the solution is An = nx+11. I added an extra day because I thought it was the fourth day after the planting, and the problem also says it grows by the constant rate on the first day it was planted so A0 = 11+x, A1 = 11+2x, etc...thanks!


A certain kudzu plant was 11 feet long on the day it was planted, and the length grows by a constant amount every day (including the first day it was planted). If this plant grew 40% between the fourth day after it was planted and the tenth day after it was planted, how many feet per day does it grow?

The length of the plant after the fourth day is \(11+4x\), where x is the growth rate per day.
The length of the plant after the tenth day is \(11+10x\).

We are given \(11+10x=1.4(11+4x)\) --> x=1 foot per day.

Hope it's clear.



Hi Bunuel,

I have a doubt
In this problem 40% growth is between 4th day and 10th day right? so how come we can multiply the 1.4(for 40 %) to 11+4x, where 11+4X is for 4th day, not the days between the 4ht and 10th.

We should multiply 1.4 to the days between 4th and 10th right?
Please help me in this
Senior Manager
Senior Manager
User avatar
Joined: 28 Apr 2012
Posts: 276
Location: India
Concentration: Finance, Technology
GMAT 1: 650 Q48 V31
GMAT 2: 770 Q50 V47
WE: Information Technology (Computer Software)
Re: Linear growth Problem  [#permalink]

Show Tags

New post 02 Jun 2013, 01:37
1
rrsnathan wrote:


Hi Bunuel,

I have a doubt
In this problem 40% growth is between 4th day and 10th day right? so how come we can multiply the 1.4(for 40 %) to 11+4x, where 11+4X is for 4th day, not the days between the 4ht and 10th.

We should multiply 1.4 to the days between 4th and 10th right?
Please help me in this


We are not comparing growth. We are comparing height.

Initial Height = 11
Constant growth everyday = x

After 4 days, height(H4) = 11 + 4x
After 10 days, height(H10) = 11 + 10x

40% growth between H4 and H10, means:
0.4 = (H10 - H4)/H4
=> 0.4*H4 = H10 - H4
=> 0.4H4 + H4 = H10
=> 1.4*H4 = H10

Substitute values,
1.4*(11+4x) = (11 + 10x)
=> x = 1 (skipped the solving part)

Alternatively,

After 4 days, height(H4) = 11 + 4x
After 10 days, height(H10) = 11 + 10x
Growth = H10 - H4 = (11+10x) - (11+4x) = 6x

% Growth: 6x/(11+4x) = 0.4
=> 6x = 0.4*(11+4x)
=>60x = 4 *(11+4x) = 44 + 16x
=> 44x = 44
=> x = 1
_________________

"Appreciation is a wonderful thing. It makes what is excellent in others belong to us as well."
― Voltaire


Press Kudos, if I have helped.
Thanks!

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 10192
Premium Member
Re: A certain kudzu plant was 11 feet long on the day it was  [#permalink]

Show Tags

New post 08 Mar 2019, 09:12
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

GMAT Club Bot
Re: A certain kudzu plant was 11 feet long on the day it was   [#permalink] 08 Mar 2019, 09:12
Display posts from previous: Sort by

A certain kudzu plant was 11 feet long on the day it was

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.