BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Lumber Yard Problem

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 46
Joined: Thu May 14, 2009 8:09 pm

Lumber Yard Problem

by RickH » Sun Aug 15, 2010 7:09 pm
Please help me with the following problem:

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?
I always get 36 but it should be 34?
Top
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Sun Aug 15, 2010 7:33 am
Thanked: 1 times

by thirst4edu » Sun Aug 15, 2010 9:03 pm
RickH wrote:Please help me with the following problem:

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?
I always get 36 but it should be 34?
Given,
20th board from top = below 16th from bottom
That means 20th from the top is actually 15th from bottom.
Hence, there are 19 boards above 15th from the bottom, which is 19+15 = 34!

Hope this helps!
"Learning never exhausts the mind."
--Leonardo da Vinci
Top
Senior | Next Rank: 100 Posts
Posts: 46
Joined: Thu May 14, 2009 8:09 pm

by RickH » Mon Aug 16, 2010 4:57 am
Thanks, now I see. It's always these kinds of problems that just mess up my Quant score
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 166
Joined: Fri Apr 03, 2009 11:16 pm
Location: India

by Mayur Sand » Mon Aug 16, 2010 9:40 am
Iam still not clear on this problem . can some one explain in more detail
Top
Senior | Next Rank: 100 Posts
Posts: 46
Joined: Thu May 14, 2009 8:09 pm

by RickH » Mon Aug 16, 2010 10:08 am
Would there be also a way to do it visually?
Top
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pm
Thanked: 215 times
Followed by:7 members

by kvcpk » Tue Aug 17, 2010 3:18 am
RickH wrote:Would there be also a way to do it visually?
1,2,3,...........18,(19/16)(20/15),14.......3,2,1

Now count them 18+1+1+14 = 34

Hope this helps!!
"Once you start working on something,
don't be afraid of failure and don't abandon it.
People who work sincerely are the happiest."
Chanakya quotes (Indian politician, strategist and writer, 350 BC-275BC)
Top
Senior | Next Rank: 100 Posts
Posts: 50
Joined: Sun Aug 15, 2010 3:00 pm
Thanked: 4 times

by Makushr1 » Tue Aug 17, 2010 6:50 am
I did it real quick by making dots on a piece of paper representing the lumber. Did 20 going down then went back up. Just make sure u read it carefully since the 20th is BELOW the 16th.
Top
Senior | Next Rank: 100 Posts
Posts: 98
Joined: Sat Feb 06, 2010 11:56 pm
Thanked: 5 times

by anantbhatia » Tue Aug 17, 2010 11:07 pm
From top:
1 2 3 4 ..... 18 19 20
x x x x ..... 17 16 15 ... 3 2 1 From Bottom

Total:18 (from top already counted) + 16 (from bottom already counted)= 34
or
19+15
or so on.. Just a simple counting problem. Hope that helps. Avoid drawing dots or logs :) Use numbers instead.
Top
Post new topic Post Reply
• Page 1 of 1