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The area of a square garden is A square feet and the perimeter is P

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zz0vlb
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The area of a square garden is A square feet and the perimeter is P [#permalink] New post   Updated on: 14 Dec 2017, 01:34
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The area of a square garden is A square feet and the perimeter is P feet. If A = 2P + 9, what is the perimeter of the garden, in feet?

A. 28
B. 36
C. 40
D. 56
E. 64
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B

Originally posted by zz0vlb on 28 Apr 2010, 08:39.
Last edited by Bunuel on 14 Dec 2017, 01:34, edited 3 times in total.
Renamed the topic and edited the question.
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   28 Apr 2010, 08:44
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zz0vlb wrote:
The area of a square garden is A square feet and the perimeter is P feet. If A=2P+9 what is the perimeter of the garden, in feet?

a.28
b.36
c.40
d.56
e.64

these type problems are similar to finding a tiny gray spot on a black paper.


IMO Answer is b. 36.

Let side be a
P = 4a
A = a^2

Sub in equation A=2P+9

a^2 = 8a +9
a^2-8a +9 = 0
a = 9 or -1

So P = 4*9 = 36.

Hope this helps
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   28 Apr 2010, 08:47
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\(A=l * l =l^2\)

\(P= 4l\)

Hence, \(l^2=2*4l+9\)
Solving \(l\) will give two values, \(l=-1\) or \(l=9\) as \(l\) cant be negative so \(l=9\)

\(P=4*9=36\)

So "B".
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   28 Apr 2010, 10:46
Solving it using the options is probably the fastest. Especially once you figure out that the side of the square is Odd.
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   28 Apr 2010, 13:46
Silvers wrote:
Solving it using the options is probably the fastest. Especially once you figure out that the side of the square is Odd.



How did you figure that out that its odd?
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   28 Apr 2010, 13:48
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gxsingh wrote:
Silvers wrote:
Solving it using the options is probably the fastest. Especially once you figure out that the side of the square is Odd.



How did you figure that out that its odd?


Oh Thats Simple, equation says

A = 2P + 9

So means area is Odd so side is the square root of the area and has to be odd.

hope this helps :)
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The area of a square garden is A square feet and the perimeter is P [#permalink] New post   24 Sep 2012, 11:30
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zz0vlb wrote:
The area of a square garden is A square feet and the perimeter is P feet. If A = 2P + 9, what is the perimeter of the garden, in feet?

A. 28
B. 36
C. 40
D. 56
E. 64


Let the side of garden be \(x\) feet, then: \(area=a=x^2\) and \(perimeter=p=4x\).

Given: \(a=2p+9\) --> \(x^2=2*4x+9\) --> solving for \(x\): \(x=-1\) (not a valid solution as \(x\) represents the length and therefore must be positive) or \(x=9\) --> \(perimeter=p=4x=36\).

Answer: B.
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   28 Sep 2012, 21:23
This is hovv i solved it

A = a^2 it is a square implies it should be a perfect square

If A = 2P+9, implies a^2 = 2p+9

a^2 = 2(28) + 9 not a perfect square
a^2 = 2(36) + 9 perfect square = 80 so a = 9 so permieter = 36 true B
a^2 = 2(40) + 9 not a perfect square
a^2 = 2(56) + 9 perfect square = 121 so a = 11 if a =11 then permiter =44 condition fails
a^2 = 2(64) + 9 not a perfect square
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   28 Sep 2012, 22:17
Area===== assume it L2.. because..L*L area..

permiter=========4L

a=2p+9...

L2=2(4L)+9.

L2-8L-9=0

L will contain two solutions.. L=-1 or +9..

-1 can not be the Length or anyside..so its 9..9*4..=36..
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   11 Jan 2015, 05:21
Hey,

This is a fairly easy problem, but I think the stem is not very clear. That because it says a=2p+9, but it doesn't clarify if this "a" is the area. Especially since before it was stated that the area is A. At least I was left wondering is "a" is the area of the side of the square.

Anyway, I did it both ways. It didn't work out as "a" being the side, so I concluded that it must be the area. And I know that it doesn't make much sense to be the side, since "p", the perimeter, cannot be less than the side. Still though I think it is not clear enough!
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   26 Jan 2015, 17:45
pacifist85 wrote:
Hey,

This is a fairly easy problem, but I think the stem is not very clear. That because it says a=2p+9, but it doesn't clarify if this "a" is the area. Especially since before it was stated that the area is A. At least I was left wondering is "a" is the area of the side of the square.

Anyway, I did it both ways. It didn't work out as "a" being the side, so I concluded that it must be the area. And I know that it doesn't make much sense to be the side, since "p", the perimeter, cannot be less than the side. Still though I think it is not clear enough!


I was thinking the same question. He said "a" not "A" .
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   26 Jan 2015, 22:30
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Salvetor wrote:
pacifist85 wrote:
Hey,

This is a fairly easy problem, but I think the stem is not very clear. That because it says a=2p+9, but it doesn't clarify if this "a" is the area. Especially since before it was stated that the area is A. At least I was left wondering is "a" is the area of the side of the square.

Anyway, I did it both ways. It didn't work out as "a" being the side, so I concluded that it must be the area. And I know that it doesn't make much sense to be the side, since "p", the perimeter, cannot be less than the side. Still though I think it is not clear enough!


I was thinking the same question. He said "a" not "A" .


Yes, the area is given as 'A' and perimeter as 'P' and the relation between them is given as A = 2P + 9
The different As seem to be a typing oversight.

You need to find the perimeter so get rid of A. Side of the square will be \(\sqrt{A}\).
So Perimeter \(P = 4*Side = 4\sqrt{A}\)
\(A = P^2/16 = 2P + 9\)
Solving, we get P = 36
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   02 May 2016, 18:08
VeritasPrepKarishma wrote:
Salvetor wrote:
pacifist85 wrote:
Hey,

This is a fairly easy problem, but I think the stem is not very clear. That because it says a=2p+9, but it doesn't clarify if this "a" is the area. Especially since before it was stated that the area is A. At least I was left wondering is "a" is the area of the side of the square.

Anyway, I did it both ways. It didn't work out as "a" being the side, so I concluded that it must be the area. And I know that it doesn't make much sense to be the side, since "p", the perimeter, cannot be less than the side. Still though I think it is not clear enough!


I was thinking the same question. He said "a" not "A" .


Yes, the area is given as 'A' and perimeter as 'P' and the relation between them is given as A = 2P + 9
The different As seem to be a typing oversight.

You need to find the perimeter so get rid of A. Side of the square will be \(\sqrt{A}\).
So Perimeter \(P = 4*Side = 4\sqrt{A}\)
\(A = P^2/16 = 2P + 9\)
Solving, we get P = 36



I used this method,but end up with a complex quadratic equation - P^2-32P-144=0 Any quick ways to solve for p from that quadratic equation?
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   02 May 2016, 18:33
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theperfectgentleman wrote:

I used this method,but end up with a complex quadratic equation - P^2-32P-144=0 Any quick ways to solve for p from that quadratic equation?


Note that the equation has negative coefficient of P and a negative constant term.
So sum of roots and product of roots both are negative. Hence one root is negative and the other positive. So at least one root will be greater than 32. Since the product of both is 144, the other root will be very small such as 2, 3 or 4. You see that 36*4 = 144 so you get the split as

P^2 - 36P + 4P - 144 = 0
(P - 36)(P + 4) = 0
P = 36
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   03 May 2016, 08:07
Let side be a
P = 4a
A = a^2

Sub in equation A=2P+9

a^2 = 8a +9
a^2-8a +9 = 0
a = 9 or -1

So P = 4*9 = 36.
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   15 Aug 2021, 07:11
zz0vlb wrote:
The area of a square garden is A square feet and the perimeter is P feet. If A = 2P + 9, what is the perimeter of the garden, in feet?

A. 28
B. 36
C. 40
D. 56
E. 64

Instead of assuming side as x or a lets assume side as sqrt(A) derived from the area A and side as P/4 derived from the perimeter. This makes sqrt(A) = P/4.
When applying this in the equation A=2P+9, we cannot find the answer, hence i feel the question has a flaw.
please help
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink] New post   22 Apr 2023, 04:55
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Re: The area of a square garden is A square feet and the perimeter is P [#permalink]
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