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A data company recently conducted a survey to determine wh [#permalink]

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08 Jun 2013, 01:11

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A data company recently conducted a survey to determine whether people use product X or product Y. If fewer than 100 people were surveyed and each person used either one product or both, how many people used product Y?

(1) 65% of survey respondents used only product X (2) 10% of survey respondents used both products X and Y

A data company recently conducted a survey to determine whether people use product X or product Y. If fewer than 100 people were surveyed and each person used either one product or both, how many people used product Y?

Given: {Total} < 100 and {Neither} = 0.

{Total} = {Only X} + {Only Y} + {Both}. Notice that this formula is different from {Total} = {X} + {Y} - {Both}.

(1) 65% of survey respondents used only product X. 65%=65/100=13/20, thus {Total} must be a multiple of 20. Not sufficient.

(2) 10% of survey respondents used both products X and Y. 10%=1/10, thus {Total} must be a multiple of 20. Not sufficient.

(1)+(2) If {Total} = 20, then {Only X} = 13/20*20 = 13, thus {Y} = {Total} - {Only X} = 7 BUT {Total} = 40, then {Only X} = 13/20*40 = 26, thus {Y} = {Total} - {Only X} = 14. Not sufficient.

Re: A data company recently conducted a survey to determine wh [#permalink]

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08 Jun 2013, 17:28

emmak wrote:

A data company recently conducted a survey to determine whether people use product X or product Y. If fewer than 100 people were surveyed and each person used either one product or both, how many people used product Y?

(1) 65% of survey respondents used only product X (2) 10% of survey respondents used both products X and Y

Just pick good numbers to fill in the answers , lets say 80 or 60. Each time with the given fact you will get a different answer.Hence E.

Given less than 100 people were surveyed St 1. X = less than 65 Does not tell anything about Y Not-Suff St. 2 Both = less than 10 - Not Suff

Together : Can be multiple ans for Y

Ans : E

Another way to look at this question . Total given is a range.Total can be any number from 1 to 99 ( total <100). (1) X is 65% of Total => X can have multiple values as total is not fixed => Not Sufficient .Unable to get a single value for Y (2)Both X & Y = 10% of Total => multiple values => Not Sufficient .Unable to get a single value for Y

(1) & (2) together also does not help to get a single value for Y.Hence answer is E

Given less than 100 people were surveyed St 1. X = less than 65 Does not tell anything about Y Not-Suff St. 2 Both = less than 10 - Not Suff

Together : Can be multiple ans for Y

Ans : E

Another way to look at this question . Total given is a range.Total can be any number from 1 to 99 ( total <100). (1) X is 65% of Total => X can have multiple values as total is not fixed => Not Sufficient .Unable to get a single value for Y (2)Both X & Y = 10% of Total => multiple values => Not Sufficient .Unable to get a single value for Y

(1) & (2) together also does not help to get a single value for Y.Hence answer is E

it's a one line solution problem. we know just one thing and it's less than 100 people, 1 to 99 anything . 99cases not only double cases.. so its not possible to evaluate how many people used Y or X or anything else, just by using % . so (E)
_________________

Re: A data company recently conducted a survey to determine wh [#permalink]

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20 Sep 2013, 17:27

I'd disagree with the suggested answer.

The answer should actually be A.

The question asks how many people use Y, not 'only' Y. So it should be the total of the # people who use only Y + the # of people who use Y and X.

If 65% of respondents used only X. And less than 100 people were surveyed, we know that the number of people who used only X must be a variable of a factor of 65 since only whole people (integers) can fit into a bucket.

Since every responder must choose one or both products and neither is not an option we know that 35% use Y.

65 and 35 are both only divisible by 5. Therefore 13 people use only X and 7 use Y or both. Therefore the answer should be A as we can determine the value is 7.

The question asks how many people use Y, not 'only' Y. So it should be the total of the # people who use only Y + the # of people who use Y and X.

If 65% of respondents used only X. And less than 100 people were surveyed, we know that the number of people who used only X must be a variable of a factor of 65 since only whole people (integers) can fit into a bucket.

Since every responder must choose one or both products and neither is not an option we know that 35% use Y.

65 and 35 are both only divisible by 5. Therefore 13 people use only X and 7 use Y or both. Therefore the answer should be A as we can determine the value is 7.

Re: A data company recently conducted a survey to determine wh [#permalink]

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22 Sep 2013, 12:09

Bunuel wrote:

A data company recently conducted a survey to determine whether people use product X or product Y. If fewer than 100 people were surveyed and each person used either one product or both, how many people used product Y?

Given: {Total} < 100 and {Neither} = 0.

{Total} = {Only X} + {Only Y} + {Both}. Notice that this formula is different from {Total} = {X} + {Y} - {Both}.

Bunuel,

what's the difference between the two formulas? when would we use the second one? thanks

A data company recently conducted a survey to determine whether people use product X or product Y. If fewer than 100 people were surveyed and each person used either one product or both, how many people used product Y?

Given: {Total} < 100 and {Neither} = 0.

{Total} = {Only X} + {Only Y} + {Both}. Notice that this formula is different from {Total} = {X} + {Y} - {Both}.

Bunuel,

what's the difference between the two formulas? when would we use the second one? thanks

The two formulas are:

{Total} = {X} + {Y} - {Both} + {Neither}

Now, since {X} = {Only X} + {Both} and {Y} = {Only Y} + {Both}, then if you substitute you get: {Total} = {Only X} + {Only Y} + {Both} + {Neither}

You should apply the one which best suits the question at hand.
_________________

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