Summer is Coming! Join the Game of Timers Competition to Win Epic Prizes. Registration is Open. Game starts Mon July 1st.

It is currently 20 Jul 2019, 05:38

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

In a stack of boards at a lumber yard, the 20th board counting from th

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

Hide Tags

Find Similar Topics 
Senior Manager
Senior Manager
User avatar
S
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 491
In a stack of boards at a lumber yard, the 20th board counting from th  [#permalink]

Show Tags

New post 17 Jun 2011, 05:09
1
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

59% (00:54) correct 41% (01:04) wrong based on 132 sessions

HideShow timer Statistics


In a stack of boards at a lumber yard, the 20th board counting from the top of the stack is immediately below the 16th board counting from the bottom of the stack. how many boards are in the stack?

A) 38

B) 36

C) 35

D) 34

E) 32

_________________
Manager
Manager
User avatar
Joined: 19 Nov 2010
Posts: 80
Re: In a stack of boards at a lumber yard, the 20th board counting from th  [#permalink]

Show Tags

New post 17 Jun 2011, 13:08
1
1 2 3 ... 14 15 16 ...................
..............20 19 ................. 1

So the number of boards = 20+14 =34
Director
Director
User avatar
V
Joined: 04 Dec 2015
Posts: 745
Location: India
Concentration: Technology, Strategy
WE: Information Technology (Consulting)
GMAT ToolKit User
Re: In a stack of boards at a lumber yard, the 20th board counting from th  [#permalink]

Show Tags

New post 04 Jul 2017, 15:44
Baten80 wrote:
In a stack of boards at a lumber yard, the 20th board counting from the top of the stack is immediately below the 16th board counting from the bottom of the stack. how many boards are in the stack?

A) 38

B) 36

C) 35

D) 34

E) 32


A board is 20th board counting from the top of the stack . Therefore it will have \(19\) boards above it.

Same board is immediately below the \(16th\) board counting from the bottom of the stack.

Therefore it is on \(15th\) number from bottom of the stack and it will have \(14\) boards below it.

Total number of boards in stack \(= 19 + 14 + 1 = 34\)

Answer (D)...

_________________
Please Press "+1 Kudos" to appreciate. :)
Senior SC Moderator
avatar
V
Joined: 22 May 2016
Posts: 3087
In a stack of boards at a lumber yard, the 20th board counting from th  [#permalink]

Show Tags

New post 05 Jul 2017, 15:42
1
Baten80 wrote:
In a stack of boards at a lumber yard, the 20th board counting from the top of the stack is immediately below the 16th board counting from the bottom of the stack. how many boards are in the stack?

A) 38

B) 36

C) 35

D) 34

E) 32
Attachment:
stack of boards.jpg
stack of boards.jpg [ 797.06 KiB | Viewed 1385 times ]


After 20 seconds of trying to do the math in my head, I sketched quickly and it got a lot easier.

I've attached a diagram.

Though there are two columns, they represent one stack.

If you were standing in front of this one stack to count boards, for the left column, you would put your finger on the top board and count downward. The right column is the same stack, only this time you have reached down and started counting from the bottom upwards. I slid the two apart to figure out where GREEN and YELLOW fell in relation to boards above and below, and to get arithmetic correct.


Call the board that is 20th counting down from the top GREEN.

That GREEN board sits one below the board that is 16th counting up from the bottom. Call that 16th-from-bottom YELLOW.

GREEN has 19 boards above it. YELLOW has 15 boards below it.

But there is overlap: GREEN takes the ordinal "counting place" of 15th board from bottom (crossed out in diagram to indicate it shouldn't be counted), and

YELLOW takes the ordinal counting place of 19th board from top counting down (also crossed out).

Don't think about the blacked out parts. In ordinal (nth) terms, they don't match, and they'll confuse, which is precisely the point of this question.

So we have 18 + 1 + 1 + 14 = 34.

Answer D

Hope it helps.

Edited to add italicized text.
_________________
SC Butler has resumed!
Get two SC questions to practice, whose links you can find by date, here.

-- Take another look. Take a look around. These are the moments you can't pass by.
Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2822
Re: In a stack of boards at a lumber yard, the 20th board counting from th  [#permalink]

Show Tags

New post 14 Jul 2017, 10:42
Baten80 wrote:
In a stack of boards at a lumber yard, the 20th board counting from the top of the stack is immediately below the 16th board counting from the bottom of the stack. how many boards are in the stack?

A) 38

B) 36

C) 35

D) 34

E) 32


If the 20th board counting from the top of the stack is immediately below the 16th board counting from the bottom of the stack, then the 19th board counting from the top of the stack is exactly the 16th board counting from the bottom of the stack. In other words, there are 18 boards above the 16th board counting from the bottom of the stack. Thus, there are 18 + 16 = 34 boards in the stack.

Answer: D
_________________

Jeffrey Miller

Head of GMAT Instruction

Jeff@TargetTestPrep.com
TTP - Target Test Prep Logo
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 11717
Re: In a stack of boards at a lumber yard, the 20th board counting from th  [#permalink]

Show Tags

New post 24 Sep 2018, 08:13
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 Club Bot
Re: In a stack of boards at a lumber yard, the 20th board counting from th   [#permalink] 24 Sep 2018, 08:13
Display posts from previous: Sort by

In a stack of boards at a lumber yard, the 20th board counting from th

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





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