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

It is currently 15 Dec 2018, 03:58

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 in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • Free GMAT Strategy Webinar

     December 15, 2018

     December 15, 2018

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.
  • $450 Tuition Credit & Official CAT Packs FREE

     December 15, 2018

     December 15, 2018

     10:00 PM PST

     11:00 PM PST

    Get the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299)

A store has a parking lot which contains 70 parking spaces. Each row

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51218
A store has a parking lot which contains 70 parking spaces. Each row  [#permalink]

Show Tags

New post 16 Oct 2017, 09:23
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

78% (03:22) correct 22% (02:33) wrong based on 39 sessions

HideShow timer Statistics

A store has a parking lot which contains 70 parking spaces. Each row in the parking lot contains the same number of parking spaces. The store has bought additional property in order to build an addition to the store. When the addition is built, 2 parking spaces will be lost from each row; however, 4 more rows will be added to the parking lot. After the addition is built, the parking lot will still have 70 parking spaces, and each row will contain the same number of parking spaces as every other row. How many rows were in the parking lot before the addition was built?

(A) 5
(B) 6
(C) 7
(D) 10
(E) 14

_________________

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

DS Forum Moderator
avatar
P
Joined: 21 Aug 2013
Posts: 1412
Location: India
Premium Member
Re: A store has a parking lot which contains 70 parking spaces. Each row  [#permalink]

Show Tags

New post 16 Oct 2017, 10:29
Let the number of rows initially be 'n'. Since each row has same number of parking spaces, and total spaces are 70, 'n' must be a factor of 70. (option B is out)

Now, after we add 4 more rows, even if we reduce number of parking spaces per row, still every row has same number of spaces and total spaces are still 70. So 'n+4' also must be a factor of 70.

So n and n+4 both must be factors of 70. Only 10 from the given options fit the value of 'n' (because 10+4 = 14 is also a factor of 70).

So D answer
Intern
Intern
avatar
B
Joined: 04 Sep 2017
Posts: 22
Location: United States
Concentration: Finance
GMAT 1: 610 Q36 V36
GMAT 2: 680 Q40 V36
GPA: 3.3
WE: Consulting (Mutual Funds and Brokerage)
Re: A store has a parking lot which contains 70 parking spaces. Each row  [#permalink]

Show Tags

New post 16 Oct 2017, 10:35
We know that there are 70 spots to begin with and 70 spots to end with.

Before the new construction we have 70=x*y where x is the number of rows and y is the # of spots per row.
After the construction we have 70=(x+4)*(y-2).

We know that both x and y must be positive integers, so I thought the best way was to find factors of 70 that fit both equations. Factors besides 70 and 1 are 10,7, 14, 5. The only way it works is if x=10 and y=7 and we are looking to solve for x, so the answer is D.
Manager
Manager
avatar
G
Joined: 01 Feb 2017
Posts: 171
A store has a parking lot which contains 70 parking spaces. Each row  [#permalink]

Show Tags

New post 23 Oct 2017, 07:18
Factors of 70=
1x70 ; 2x35 ; 5x14 ; 7x10

Now, given that one factor is reduced by 2 and other increased by 4 to retain same value, we know that
7x10 changed to (7-2)x(10+4) i.e. 5x14.

As number of rows increased by 4, we can deduce from above that initially there were 10 rows.

Hence, Ans D
GMAT Club Bot
A store has a parking lot which contains 70 parking spaces. Each row &nbs [#permalink] 23 Oct 2017, 07:18
Display posts from previous: Sort by

A store has a parking lot which contains 70 parking spaces. Each row

  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®.