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# A survey was conducted to determine the popularity of 3 food

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Intern
Joined: 24 Jan 2012
Posts: 9
A survey was conducted to determine the popularity of 3 food  [#permalink]

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26 Sep 2013, 07:27
15
93
00:00

Difficulty:

95% (hard)

Question Stats:

58% (02:47) correct 42% (02:43) wrong based on 1126 sessions

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A survey was conducted to determine the popularity of 3 foods among students. The data collected from 75 students are summarized as below

48 like Pizza
45 like Hoagies
58 like tacos
28 like pizza and hoagies
37 like hoagies and tacos
40 like pizza and tacos
25 like all three food

What is the number of students who like none or only one of the foods ?

A. 4
B. 16
C. 17
D. 20
E. 23

I got this one right but I spent a lot of time playing with numbers. Can someone please show a faster way.
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A survey was conducted to determine the popularity of 3 food  [#permalink]

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28 Sep 2013, 03:35
17
36
violetsplash wrote:
A survey was conducted to determine the popularity of 3 foods among students. The data collected from 75 students are summarized as below

48 like Pizza
45 like Hoagies
58 like tacos
28 like pizza and hoagies
37 like hoagies and tacos
40 like pizza and tacos
25 like all three food

What is the number of students who like none or only one of the foods ?

A. 4
B. 16
C. 17
D. 20
E. 23

I got this one right but I spent a lot of time playing with numbers. Can someone please show a faster way.

$$Total = A + B + C - (sum \ of \ 2-group \ overlaps) + (all \ three) + Neither$$.

75 = 48 + 45 + 58 - (28 + 37 + 40) + 25 + Neither --> Neither = 4.

Only Pizza = P - (P and H + P and T - All 3) = 48 - (28 + 40 - 25) = 5;
Only Hoagies = H - (P and H + H and T - All 3) = 45 - (28 + 37 - 25) = 5;
Only Tacos = T - (P and T + H and T - All 3) = 58 - (40 + 37 - 25) = 6.

The number of students who like none or only one of the foods = 4 + (5 + 5 + 6) = 20.

Hope this helps.
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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27 Sep 2013, 19:30
39
15
violetsplash wrote:
A survey was conducted to determine the popularity of 3 foods among students. The data collected from 75 students are summarized as below

48 like Pizza
45 like Hoagies
58 like tacos
28 like pizza and hoagies
37 like hoagies and tacos
40 like pizza and tacos
25 like all three food

What is the number of students who like none or only one of the foods ?

A. 4
B. 16
C. 17
D. 20
E. 23

I got this one right but I spent a lot of time playing with numbers. Can someone please show a faster way.

I have edited the question. The total number of students was missing. After that I could solve it as well. The updated solution is attached.
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Solution.jpg [ 81.28 KiB | Viewed 57986 times ]

##### General Discussion
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A survey was conducted to determine the popularity of 3 food  [#permalink]

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29 Sep 2014, 11:23
Bunuel / VeritasPrepKarishma, is there a simpler method similar to the table method used for such problems? This appeared in the first 10 questions of my test and I was stumped by the numbers involved.
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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30 Sep 2014, 07:58
14
3
nitin6305 wrote:
Is there a simpler method similar to the table method used for such problems? This appeared in the first 10 questions of my test and I was stumped by the numbers involved.

Make a Venn diagram. The toughest of sets questions can be done easily through venn diagrams because you can visualize easily.

Draw three overlapping circles (as shown by Bunuel in his post above). Mark set A as Pizzas, set B as Hoagies and set C as Tacos.
The part where all three overlap (g in the diagram), mark that as 25.
28 like pizza and hoagies. 25 like all three so 3 like only pizzas and hoagies. Mark d as 3.
37 like hoagies and tacos. 25 like all three so 12 like only hoagies and tacos. Mark f as 12.
40 like pizza and tacos. 25 like all three so 15 like only pizza and tacos. Mark e as 15.

From 75, subtract d, e, f and g. This will give the number of students lying in a, b, c and None. This is exactly what we want.
75 - 3 - 12 - 15 - 25 = 20
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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23 Nov 2014, 11:06
This one is tricky and lengthy , I guess it doesnt end there in Knowing your Formula 1 and Formula 2 :D ..... I tried solving this and then I got stuck again solving for exactly 1 like . Though it was preety straight forward for solving Neither .

Also I recognize something , for the same problem I can also number of people who like exactly 2 like

using

Total = A+B+C - ( Exactly 2 like AB+BC+CA) - 2 ABC +Neither.

Hence

75 = 151 - Exactly 2 like - 2 (25) + 4

Exactly 2 like =26 .

Correct me if I am missing something .I guess though its the right approach . Also for this we need to primarily work 1st step Using Formula 1 to find Neither . Then only its possible . Suggest me if there is any other approach
Thanks.

Bunuel wrote:
violetsplash wrote:
A survey was conducted to determine the popularity of 3 foods among students. The data collected from 75 students are summarized as below

48 like Pizza
45 like Hoagies
58 like tacos
28 like pizza and hoagies
37 like hoagies and tacos
40 like pizza and tacos
25 like all three food

What is the number of students who like none or only one of the foods ?

A. 4
B. 16
C. 17
D. 20
E. 23

I got this one right but I spent a lot of time playing with numbers. Can someone please show a faster way.

$$Total = A + B + C - (sum \ of \ 2-group \ overlaps) + (all \ three) + Neither$$.

75 = 48 + 45 + 58 - (28 + 37 + 40) + 25 + Neither --> Neither = 4.

Only Pizza = P - (P and H + P and T - All 3) = 48 - (28 + 40 - 25) = 5;
Only Hoagies = H - (P and H + H and T - All 3) = 45 - (28 + 37 - 25) = 5;
Only Tacos = T - (P and T + H and T - All 3) = 58 - (40 + 37 - 25) = 5.

The number of students who like none or only one of the foods = 4 + (5 + 5 + 6) = 20.

Hope this helps.
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Posts: 16
Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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23 Nov 2014, 11:23
How are we assuming about the neither part to be . I mean when we are subtracting (All three) from each of the (2 like region )

we assume that its part of the bigger a , b and c .

I mean suppose we try solving for Exactly two like using the approach above then we have ,

All 2 like = (28-25)= 3 ; (37-25)=12 ; (40-25)=15 ; Therefore 3+12+15=30 .....But I guess its wrong as I am missing out on the Neither Part.

Now If I consider the approach used by Bruneal then I know that Neither =4 ; so Exactly liking 2 items would be 30-4=26 .

Please correct me if I am wrong , also what approach should I take for Neither.

VeritasPrepKarishma wrote:
nitin6305 wrote:
Is there a simpler method similar to the table method used for such problems? This appeared in the first 10 questions of my test and I was stumped by the numbers involved.

Make a Venn diagram. The toughest of sets questions can be done easily through venn diagrams because you can visualize easily.

Draw three overlapping circles (as shown by Bunuel in his post above). Mark set A as Pizzas, set B as Hoagies and set C as Tacos.
The part where all three overlap (g in the diagram), mark that as 25.
28 like pizza and hoagies. 25 like all three so 3 like only pizzas and hoagies. Mark d as 3.
37 like hoagies and tacos. 25 like all three so 12 like only hoagies and tacos. Mark f as 12.
40 like pizza and tacos. 25 like all three so 15 like only pizza and tacos. Mark e as 15.

From 75, subtract d, e, f and g. This will give the number of students lying in a, b, c and None. This is exactly what we want.
75 - 3 - 12 - 15 - 25 = 20
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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23 Nov 2014, 19:39
3
4
hanschris5 wrote:
How are we assuming about the neither part to be . I mean when we are subtracting (All three) from each of the (2 like region )

we assume that its part of the bigger a , b and c .

I mean suppose we try solving for Exactly two like using the approach above then we have ,

All 2 like = (28-25)= 3 ; (37-25)=12 ; (40-25)=15 ; Therefore 3+12+15=30 .....But I guess its wrong as I am missing out on the Neither Part.

Now If I consider the approach used by Bruneal then I know that Neither =4 ; so Exactly liking 2 items would be 30-4=26 .

Please correct me if I am wrong , also what approach should I take for Neither.

The question asks you the sum of 'None' and 'Only 1' i.e. it asks you 'None + Only 1' (irrespective of how many are in None and how many are in Only 1). You just need the sum.

You have that the total number of students = 75

75 = None + Only 1 + Only 2 + All 3
To get 'None + Only 1', all you need to do is subtract 'Only 2' and 'All 3' from 75.

'Only 2' =3 + 12 + 15 = 30 (as correctly calculated by you. It does not include 'None')
'All 3' = 25

So None + Only 1 = 75 - 30 - 25 = 20
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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25 Dec 2014, 04:00
5
1
There's a faster way of doing it.
Let x= total with 3 foods
Total with with 2 foods only => (37-x) + (28-x) + (40-x) = 105-3x= 30
Total with 3 = x = 25

Total 0 and 1 = Total - (Total 2 and Total 3)
= 75 - 30 - 25
= 20
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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12 Feb 2015, 06:20
Dear Bunuel,
I think in your solution, you intended to use the second formula from the gmatclub mathbook,but wrote the first formula.
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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12 Feb 2015, 06:33
vards wrote:
Dear Bunuel,
I think in your solution, you intended to use the second formula from the gmatclub mathbook,but wrote the first formula.

Can you elaborate on this? Why is the formula used wrong?
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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03 Jul 2015, 03:08
I'd appreciate further clarification on why we use the version of the formula where we add back in the 'all' category? I'm not sure why we are able to assume that the 'all' category also includes numbers from the 'two items' sections? Thanks
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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03 Jul 2015, 03:11
ElCorazon wrote:
I'd appreciate further clarification on why we use the version of the formula where we add back in the 'all' category? I'm not sure why we are able to assume that the 'all' category also includes numbers from the 'two items' sections? Thanks

Hope this helps.
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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03 Jun 2016, 09:15
3
1
When you draw the Venn diagram, I suggest starting with the "triple overlap" number of 25 and working your way out from there. Don't forget to adjust the numbers as you go.

Attached is a visual that should help.
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Screen Shot 2016-06-03 at 10.14.20 AM.png [ 112.84 KiB | Viewed 35430 times ]

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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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12 Oct 2017, 18:16
violetsplash wrote:
A survey was conducted to determine the popularity of 3 foods among students. The data collected from 75 students are summarized as below

48 like Pizza
45 like Hoagies
58 like tacos
28 like pizza and hoagies
37 like hoagies and tacos
40 like pizza and tacos
25 like all three food

What is the number of students who like none or only one of the foods ?

A. 4
B. 16
C. 17
D. 20
E. 23

I got this one right but I spent a lot of time playing with numbers. Can someone please show a faster way.

The thing that's important to remember with this time of problem is that it says "37 like hoagies and tacos" not "37 like only hoagies and tacos" ---> knowing this we can apply the first of 2 formulas used for 3 overlapping sets

total= A + B + C - [sum of 2] + [all three] + neither
75= 71 + x
Neither= 4

Work in reverse to find the number of exactly 2

D
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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20 Jul 2018, 09:54
The question could be solved in two parts:-

1) First 75 minus the number contained in union of the three sets will give the number of students who like none of the foods.(i.e. 75-71=4)
2) In second part, number of students who like only one of the foods = (71-55=16)

Total = 4+16 = 20

Option D is the correct answer.
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Re: A survey was conducted to determine the popularity of 3 food  [#permalink]

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01 Sep 2018, 22:39
CAMANISHPARMAR wrote:
The question could be solved in two parts:-

1) First 75 minus the number contained in union of the three sets will give the number of students who like none of the foods.(i.e. 75-71=4)
2) In second part, number of students who like only one of the foods = (71-55=16)

Total = 4+16 = 20

Option D is the correct answer.

CAMANISHPARMAR, how do you find 4 from first part (or 71)?
Re: A survey was conducted to determine the popularity of 3 food &nbs [#permalink] 01 Sep 2018, 22:39
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