square picture

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square picture

by sairamGmat » Mon Aug 09, 2010 4:07 pm
A square picture frame has an outer perimeter of 36 inches and is 1 inch wide on all sides. What is the inner perimeter of the frame, in inches?
(A) 27
(B) 27 1/2
(C) 28
(D) 31 1/2
(E) 32

OA is C

Not sure whether it is correct..I thought it is E

Any light into this?

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by selango » Mon Aug 09, 2010 4:46 pm
Outer frame
--------------

Perimeter 4a=36

a=9

It is 1 inch wide.

so the inner frame side length=9-1-1=7

Perimeter of inner side=4*side=4*7

=28

Pick C
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by Rahul@gurome » Mon Aug 09, 2010 4:47 pm
sairamGmat wrote:A square picture frame has an outer perimeter of 36 inches and is 1 inch wide on all sides. What is the inner perimeter of the frame, in inches?
(A) 27
(B) 27 1/2
(C) 28
(D) 31 1/2
(E) 32

OA is C

Not sure whether it is correct..I thought it is E

Any light into this?
Image

AB + BC + CD + DA = 36 in.

As shown in the figure, from each side we'll subtract 2 in.. which means we subtract 8 from the perimeter of the outer square to get the perimeter of the inner square.

So, 36 - 8 = 28 in.

The correct answer is [spoiler](C)[/spoiler].
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by Spidy001 » Thu Mar 31, 2011 4:09 am
Outer perimeter = 36 => outer square side = 9

inner square is layed out in such a way it leaves 1 inch width on all its sides

inner square side = 9 - 1-1 = 7

permiter of inner square = 4*7 =28

Answer is C.

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by lunarpower » Fri Apr 01, 2011 4:09 am
the solution given by rahul is perfect.

if you thought that the inner frame was 8 x 8, then that means you didn't draw a diagram! if you draw even a crude diagram of the situation, it becomes quite obvious that you need to subtract 2 inches, not just 1 inch, from each side of the original square.

ALWAYS draw diagrams for geometry problems that don't already have diagrams!
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by sushantgupta » Sun May 01, 2011 10:34 pm
Answer is C

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by MBA.Aspirant » Tue Aug 02, 2011 7:40 am
side of outer frame = 36/4 = 9

subtract 1 twice from the outer frame to get the inner frame side= 9-2 = 7


perimeter = 7*4 = 28

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by gdiwan » Tue Aug 16, 2011 12:43 pm
answer is C.

selango wrote:Outer frame
--------------

Perimeter 4a=36

a=9

It is 1 inch wide.

so the inner frame side length=9-1-1=7

Perimeter of inner side=4*side=4*7

=28

Pick C

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by JS_2 » Mon Sep 12, 2011 9:54 pm
my ans Is (C)
Just subtract 2 from each side!

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by Abhishek009 » Tue Sep 13, 2011 6:45 am
sairamGmat wrote:A square picture frame has an outer perimeter of 36 inches and is 1 inch wide on all sides. What is the inner perimeter of the frame, in inches?
(A) 27
(B) 27 1/2
(C) 28
(D) 31 1/2
(E) 32

OA is C

Not sure whether it is correct..I thought it is E

Any light into this?
There is a cool formula for solving such problem as follows :

Outer Perimeter = P

Width of the Square is = w

So Inner Perimeter is :

{ p / 4 - 2*w } * 4



Applying the formula :

P = 36

w = 1

So { p / 4 - 2*w } * 4

{36 / 4 - 2* ( 1 )}* 4

( 9 - 2 ) * 4

28 inches...



The logic behind it is very well explained by other users , so not going in such details...
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by parul9 » Sat Oct 08, 2011 7:46 pm

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by olylo » Wed Nov 02, 2011 4:19 am
Yes it is C

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by gmatblood » Wed Nov 02, 2011 4:50 am
IMO: 28

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by Deependra1 » Tue Nov 08, 2011 2:46 am
Answer: C

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by AvishekShaw » Tue Aug 07, 2012 11:19 pm
C indeed.