Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 05 May 2015, 17:34

### 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 June
Open Detailed Calendar

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

Author Message
TAGS:
Intern
Joined: 12 Nov 2007
Posts: 3
Followers: 0

Kudos [?]: 0 [0], given: 0

In a stack of boards at a lumber yard, the 20th board [#permalink]  12 Nov 2007, 19:45
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

I can find the answer easily enough by writing down all the numbers and back solving using the answers, but there has to be an easier way to attack this problem. Any ideas?
Manager
Joined: 25 Jul 2007
Posts: 108
Followers: 1

Kudos [?]: 14 [0], given: 0

There is no need to backsolve.

We will call our board B. It says that the board is 20th from the top of the stack.
i.e:

19
B
..
...

It also says that this board B is one below the 16th board from the bottom. i.e. it is the 15th board from the bottom.

19
B
14

19+B+14=34 boards in the stack.

Hope this helps.
Director
Joined: 09 Aug 2006
Posts: 766
Followers: 1

Kudos [?]: 69 [0], given: 0

Re: Counting Problems [#permalink]  12 Nov 2007, 20:26
showtime12 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

I can find the answer easily enough by writing down all the numbers and back solving using the answers, but there has to be an easier way to attack this problem. Any ideas?

From the top, the board after the 19th board, i.e., the 20th board from the top is the 15th board from the bottom. Total boards = 19 + 15 = 34.
Intern
Joined: 12 Nov 2007
Posts: 3
Followers: 0

Kudos [?]: 0 [0], given: 0

Re: Counting Problems [#permalink]  13 Nov 2007, 11:38
That makes sense. Thanks

showtime12 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

I can find the answer easily enough by writing down all the numbers and back solving using the answers, but there has to be an easier way to attack this problem. Any ideas?
Re: Counting Problems   [#permalink] 13 Nov 2007, 11:38
Similar topics Replies Last post
Similar
Topics:
CPA as a spring board to MBA as a spring board to.. 3 26 Jun 2011, 13:53
1 Stack of Boards 1 17 Jun 2011, 04:09
44 As the former chair of the planning board for 18 consecutive 17 08 Sep 2008, 18:24
Stack of boards Qs 2 24 Mar 2007, 19:13
11 In a stack of boards at a lumber yard, the 20th board 10 14 Nov 2006, 12:59
Display posts from previous: Sort by