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

 It is currently 22 Jan 2019, 05:02

### 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

## Events & Promotions

###### Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### The winners of the GMAT game show

January 22, 2019

January 22, 2019

10:00 PM PST

11:00 PM PST

In case you didn’t notice, we recently held the 1st ever GMAT game show and it was awesome! See who won a full GMAT course, and register to the next one.
• ### Key Strategies to Master GMAT SC

January 26, 2019

January 26, 2019

07:00 AM PST

09:00 AM PST

Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.

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

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 22 Sep 2005
Posts: 262
In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

Updated on: 03 Sep 2012, 04:12
8
41
00:00

Difficulty:

45% (medium)

Question Stats:

60% (00:37) correct 40% (00:39) wrong based on 1291 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

Originally posted by netcaesar on 14 Nov 2006, 12:59.
Last edited by Bunuel on 03 Sep 2012, 04:12, edited 2 times in total.
Math Expert
Joined: 02 Sep 2009
Posts: 52385
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

03 Sep 2012, 04:18
11
11
vidhya16 wrote:
Guys,

Im confused with the phrase "immediately below 16 from the bottom". When you count something and you say immediately below something doesnt that it mean next number in the counting. In this example it will be 17th. How do you guys say it is 15th from the bottom?

Any clarification will help on Tuesday attempt.

Thanks

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

There are some number of boards stacked.

20th board from the top is immediately below the 16th board from the bottom:

1
2
3
.
.
.
16
20 15
14
13
.
.
.
3
2
1

As you can see 20th board from the top is immediately below the 16th board from the bottom. The total number of boards 20(red)+14(blue)=34.

_________________
##### General Discussion
Senior Manager
Joined: 08 Jun 2006
Posts: 323
Location: Washington DC

### Show Tags

14 Nov 2006, 13:32
2
2
20th board from top is 15th (immediately below the 16th board) from bottom. Therefore, there are 14 more boards below the 20th board (from top).
Total number of boards = 34
Manager
Joined: 29 Aug 2006
Posts: 155

### Show Tags

14 Nov 2006, 13:42
1
This is where I generally tend to make mistakes, hence I do it the manual way.
Director
Joined: 21 Aug 2006
Posts: 931

### Show Tags

15 Nov 2006, 05:57
16 th above 20th..

so 20th is 15th..there are 14 under that..total is 34
_________________

The path is long, but self-surrender makes it short;
the way is difficult, but perfect trust makes it easy.

Director
Joined: 12 Jun 2006
Posts: 516

### Show Tags

21 Nov 2006, 15:12
2
Algebraically:
x-19=15
x=34
Senior Manager
Joined: 01 Sep 2006
Posts: 297
Location: Phoenix, AZ, USA
Re: PS: Stack of boards  [#permalink]

### Show Tags

21 Nov 2006, 23:10
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

123456789 10 11 12 13 14 15 16 17 18 19 20
16 15 14 13 .... 1

18+16=34
Intern
Joined: 08 Jan 2012
Posts: 6
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

02 Sep 2012, 07:17
Guys,

Im confused with the phrase "immediately below 16 from the bottom". When you count something and you say immediately below something doesnt that it mean next number in the counting. In this example it will be 17th. How do you guys say it is 15th from the bottom?

Any clarification will help on Tuesday attempt.

Thanks
Manager
Joined: 16 Feb 2012
Posts: 174
Concentration: Finance, Economics
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

04 Sep 2012, 02:52
20th from the top is 15th form the bottom, so there are 14 more boards below the first 20...which is 34 total.
_________________

Kudos if you like the post!

Failing to plan is planning to fail.

Manager
Joined: 25 Apr 2013
Posts: 58
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

19 Feb 2015, 08:02
2
1
We can actually quickly try it out with lesser number of planks.

Say 4th from the top is immediately below 3rd from the bottom.

-------------
-------------
-------------
-------------
-------------

Total number of planks = 4+3-2 = 5

This in fact would be the case with any plank. For example, 3rd from the top is below 4th from the bottom.

Total number of planks = 3+4-2 = 5

Here, 20th from the top is below 16th from the bottom
-> Total number of planks = 20+16-2 = 34
SVP
Joined: 06 Nov 2014
Posts: 1877
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

18 Oct 2015, 11:18
novice12 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

We need the 20th board, when we start counting from the top.
This board is immediately below the 16th board from the bottom. i.e. This is the 15th board from the bottom
Hence we have 14 more boards below this.

Total number of boards = 14(No. of boards below the one in consideration) + 20(No. of boards above the one in consideration) = 34 Option D
CEO
Joined: 11 Sep 2015
Posts: 3355
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

13 Jan 2018, 09:09
Top Contributor
netcaesar 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

Let's start from the bottom and work our way up:

We'll start with the 16th board counting from the bottom of the stack

Right BELOW that 16th board, we have a board that we'll call Larry.
So, Larry is the 15th board counting from the bottom of the stack.
So, starting from the bottom and working our way up to Larry, we have 15 boards so far.

Larry is the 20th board counting from the TOP of the stack
In other words, there are 19 boards ABOVE Larry.
So, including those 19 boards, we now have 34 boards in TOTAL.

Cheers,
Brent
_________________

Test confidently with gmatprepnow.com

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 13368
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

15 Mar 2018, 12:30
Hi All,

Since the answers to the question are all numbers, we can use the answers 'against' the prompt and TEST THE ANSWERS. Here's how…

IF the number of boards was 36, then the 20th board from the top would be the 17th board from bottom, which would be UNDER the 18th board from the bottom. This is NOT a match for what we were told. Elimate B. Now we know that the number of boards has to be SMALLER. Let's test D next.

IF the number of boards was 34, then the 20th board from the top would be the 15th board from the bottom, which would be UNDER the 16th board from the bottom. This IS a match for what we were told, so this MUST be the answer.

GMAT assassins aren't born, they're made,
Rich
_________________

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

# Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save \$75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

*****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*****

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4596
Location: United States (CA)
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

30 Mar 2018, 09:59
2
netcaesar 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.

_________________

Scott Woodbury-Stewart
Founder and CEO

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

Manager
Joined: 24 Sep 2018
Posts: 139
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

07 Oct 2018, 21:40
vidhya16 wrote:
Guys,

Im confused with the phrase "immediately below 16 from the bottom". When you count something and you say immediately below something doesnt that it mean next number in the counting. In this example it will be 17th. How do you guys say it is 15th from the bottom?

Any clarification will help on Tuesday attempt.

Thanks

vidhya16,

Hey If this pictorial representation helps you.

Attachment:

IMG_2762.jpg [ 1.35 MiB | Viewed 4779 times ]

_________________

Please award kudos, If this post helped you in someway.

Intern
Joined: 09 Apr 2017
Posts: 31
GPA: 3.99
Re: In a stack of boards at a lumber yard, the 20th board  [#permalink]

### Show Tags

04 Dec 2018, 09:40
1
Posted from my mobile device
Attachments

E68D1F8A-38CD-40E5-9716-A83F53D26438.jpeg [ 512.63 KiB | Viewed 2173 times ]

Re: In a stack of boards at a lumber yard, the 20th board &nbs [#permalink] 04 Dec 2018, 09:40
Display posts from previous: Sort by