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# Of the 75 houses in a certain community, 48 have a patio. How many of

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SVP
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Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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Updated on: 17 Jul 2019, 23:31
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Question Stats:

45% (01:58) correct 55% (01:57) wrong based on 678 sessions

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Of the 75 houses in a certain community, 48 have a patio. How many of the houses in the community have a swimming pool?

(1) 38 of the houses in the community have a patio but do not have a swimming pool.

(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

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Originally posted by bmwhype2 on 21 Feb 2008, 13:37.
Last edited by Bunuel on 17 Jul 2019, 23:31, edited 1 time in total.
Renamed the topic and edited the question.
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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31 Dec 2009, 10:19
19
8
Here is my standard approach to solve such problems
P= # of houses with patio only.
Q= # of houses with pool only.
R= # of houses with patio & pool.
S= # of houses with no patio & no pool.

Given P+Q+R+S=75
& P+R=48
What is Q+R? (1)

Solving the first two equations
Q+S+48=75
Q+S=27 (2)

Now let's look at the statements
Statement 1
P=38 unnecessary and insufficient.

Statement 2
R=S
Substituting in (1)
Q+S?
We know form (2) that Q+S=27
hence sufficient.
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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21 Feb 2008, 22:58
2
1
B
--
From B, we have
x = number of houses without P and S = number of houses having P and S

75-x = P + S - x; 75=48+S; S=27
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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26 Feb 2008, 07:27
7
2
bmwhype2 wrote:
Of the 75 houses in a certain community, 48 have a patio. How many of the houses in the community have a swimming pool?

(1) 38 of the houses in the community have a patio but do not have a swimming pool.
(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

finally can got my computer log in for work... so I can participate on GClub when I have nuffin to do.

Tricky problem. This is why its important to write everything out and not do it in your head.

youl notice we want x+z, which = m.

notice carefully that x+z also =27... its that simple, but so easy to miss... I missed it and said C at first.

B
Attachments

Matrix problem.xls [13.5 KiB]

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Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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16 Aug 2009, 18:32
7
I dont know how to draw table here... attached a document file with the solution, let me know is that clear for you..
Attachments

File comment: Solution attached

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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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17 Aug 2009, 04:31
Of the 75 houses in a certain community,48 have a patio.How many of the houses in the community have a swimming pool?
1. 38 of the houses in the community have a patio but do not have a swimming pool.
2. The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

Total = only s + only p + Neither -Both
Now, lets forget about stmt 1 for now.

We have, total =75, neither=both=x, and from the stem we have 48 houses with patio ( these 48 can include houses with Only patio or Both. So we are not sure if we can take s=48 in the above formula.

I may be wrong...not sure.
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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17 Aug 2009, 06:55
2
Economist wrote:
( these 48 can include houses with Only patio or Both. So we are not sure if we can take s=48 in the above formula.

I may be wrong...not sure.

since only is not given in the question , 48 includes both houses that contains patio with swimming pool and patio without swimming pool.. did you go through the document attached, i think that is very clear...
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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24 Jul 2013, 06:20
7
6
We have to find the value of X + Y = ?

we know from statement 1 that 10 is the area covered by both and 38 is only patio we have no info about neither not sufficient

Statement 2

We have 48 - x + x + y + x = 75

we can find the value for x + y = 27 sufficient

Good problem
Attachments

Venn diagram.jpg [ 7.99 KiB | Viewed 37736 times ]

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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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09 Jan 2014, 04:49
3
We have a universal formula: Total= A + B - Both(A&B) + Neither

(1) is obviously insufficient.

(2) is sufficient because from the given conditions we get this: Both(A&B) = Neither = T(Let it be T, to make it simple)
=> 75 = 48 + B - T + T => B = 27.

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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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01 Sep 2014, 01:23

My Reasoning ;From the main question and also from statement 1-> it is apparent that all the houses have a swimming pool or a Patio. Hence you can answer the question with just A.

Statement B introduces that some houses do no have either. Also you can answer the question with statement B.

Thanks and kudos to every one
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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01 Sep 2014, 01:37
shriramvelamuri wrote:
Of the 75 houses in a certain community, 48 have a patio. How many of the houses in the community have a swimming pool?

(1) 38 of the houses in the community have a patio but do not have a swimming pool.
(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

My Reasoning ;From the main question and also from statement 1-> it is apparent that all the houses have a swimming pool or a Patio. Hence you can answer the question with just A.

Statement B introduces that some houses do no have either. Also you can answer the question with statement B.

Thanks and kudos to every one

Why it is obvious that all houses there have either a patio or a swimming pool? Why there could not be a house without either of them?
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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24 Nov 2015, 12:47
Did anyone tried solving this problem with double matrix? One of the guys did, but looks like his excel is incomplete
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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01 May 2016, 08:22
4
Keats wrote:
Did anyone tried solving this problem with double matrix? One of the guys did, but looks like his excel is incomplete

using double set matrix and from option B, we can solve as below

S.P = swimming pool
Attachments

double set.png [ 3.74 KiB | Viewed 6891 times ]

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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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05 Aug 2016, 16:30
2
bmwhype2 wrote:
Of the 75 houses in a certain community, 48 have a patio. How many of the houses in the community have a swimming pool?

Given the question, we have the following table:

$$\begin{array}{c|cc|c} & \textbf{P} & \textbf{NP} & \\ \hline \textbf{S} & A & B & \color{green}{Z} \\ \textbf{NS} & C & D & \\ \hline & 48 & 27 & 75 \\ \end{array}$$

(1) 38 of the houses in the community have a patio but do not have a swimming pool.

$$\begin{array}{c|cc|c} & \textbf{P} & \textbf{NP} & \\ \hline \textbf{S} & A & B & \color{green}{Z} \\ \textbf{NS} & 38 & D & \\ \hline & 48 & 27 & 75 \\ \end{array}$$

$$A = 10$$

We have no way of determining $$B$$

Insufficient

(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

$$\begin{array}{c|cc|c} & \textbf{P} & \textbf{NP} & \\ \hline \textbf{S} & X & B & \color{green}{Z} \\ \textbf{NS} & C & X & \\ \hline & 48 & 27 & 75 \\ \end{array}$$

We can see that although we cannot solve the matrix, we can see that a vertical and horizontal equation are equal due to the added symmetry.

$$B + X = 27 \implies Z = 27$$

Sufficient

(B) statement 2 alone is sufficient, but statement 1 alone is not sufficient to answer the question

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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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06 Aug 2016, 05:41
Top Contributor
Let,
# of houses with patio=n(P)
# of houses with Swimming pool=n(S)
# of houses with patio & Swimming pool=n(Sum of two groups overlap)
# of houses with no patio & no Swimming pool=N
So,
48+n(S)-n(Sum of two groups overlap)+N=75

(1) No information about the number of houses with no patio & no Swimming pool(N), Not sufficient

(2) statement said that, n(Sum of two groups overlap)=N,So we can find n(S)=75-48=27 , Sufficient

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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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02 Feb 2017, 17:20
2
The matrix is a great way to solve these questions, but we can solve even quicker if we know the overlapping sets formula:

Total # of items = # in group 1 + # in group 2 + neither - both

From the original, we have:

75 = 48 + swimming pool + neither - both

(2) tells us that neither = both, or that neither - both = 0. Subbing into the equation we now get:

75 = 48 + swimming pool + 0

which we can certainly solve.
Hence B.
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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21 Apr 2018, 05:31
keats wrote:
Did anyone tried solving this problem with double matrix? One of the guys did, but looks like his excel is incomplete

Yes, i was at the beginning a bit confused. But finally got it:

Here is a general formula:

A + B - Both + Neither

from question:
48 + S - Both + Neither = 75

Statement 1
38 have patio but no swimming pool

then formula becomes:
(48-38) + S - Both + Neither = 75
10 + S - Both + Neither = 75 ----> Is this sufficient to find S? No, therefore not sufficient. Why? because you are left with three variables - S,Both and Neither with one equation

Statement 2
Both = Neither

this means either we can replace from formula Both or Neither like this:

from question:
48 + S - Both + Neither = 75

Replacing "Both"
48 + S - Neither + Neither = 75 -----> you can see that Neither cancels out
then you are left with 48 + S = 75, from here you don't need to solve it since you can find the value of S Sufficient

Replacing "Neither"
48 + S - Both + Both = 75 -----> you can see that "Both" cancels out
then you are left with 48 + S = 75 same outcome as above.

My point is either way will eliminate both and neither in the formula.
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Re: Of the 75 houses in a certain community, 48 have a patio. How many of  [#permalink]

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02 Feb 2019, 12:27
The easiest way to solve this question is to draw a table.

With the information given in the question stem, the table looks like this:
Attachment:

2.PNG [ 4.12 KiB | Viewed 198 times ]

We want to find x.

Statement (1) is clearly insufficient from filling in the boxes.
Attachment:

Capture.PNG [ 4.62 KiB | Viewed 197 times ]

Statement (2) seems wordy, but is as simple as the table below:
Attachment:

2.PNG [ 4.12 KiB | Viewed 198 times ]

$$(x-y) + y = 27$$

Therefore, $$x = 27$$
Attachments

3.PNG [ 4.33 KiB | Viewed 197 times ]

Re: Of the 75 houses in a certain community, 48 have a patio. How many of   [#permalink] 02 Feb 2019, 12:27
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