PS: Percents question help

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PS: Percents question help

by Santi » Wed Aug 10, 2011 7:09 pm
Hi All,

Hoping someone can help me with the following problem solving percents question:

"A magazine's survey of its subscribers finds that 20% are male. If 70% of the subscribers are married, and 10% of these are male, what percent of the male subscribers are not married?"

My set-up has looked something like this: [(.70)(x).10 + (.30)(x) ?] =.20x, where x is the total number of subscribers and ? is the % of not-married male subscribers. Somehow I managed to get the right answer, but I think I just got lucky and my logic is wrong.

This is my first post, and if I made some moronic mistake or this it is all wrong, all I ask is that you be gentle!haha

Appreciate the help!

-Santiago

ps Answer choices are: a) 7% b) 13% c) 35% d) 65% e) 90%
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by GMATGuruNY » Wed Aug 10, 2011 7:59 pm
Santi wrote:Hi All,

Hoping someone can help me with the following problem solving percents question:

"A magazine's survey of its subscribers finds that 20% are male. If 70% of the subscribers are married, and 10% of these are male, what percent of the male subscribers are not married?"

My set-up has looked something like this: [(.70)(x).10 + (.30)(x) ?] =.20x, where x is the total number of subscribers and ? is the % of not-married male subscribers. Somehow I managed to get the right answer, but I think I just got lucky and my logic is wrong.

This is my first post, and if I made some moronic mistake or this it is all wrong, all I ask is that you be gentle!haha

Appreciate the help!

-Santiago

ps Answer choices are: a) 7% b) 13% c) 35% d) 65% e) 90%
Use a group grid to organize the information:
Image

Fill in the given information:
20 are male
70 are married
.1*70 = 7 of the married people are male

Image

Complete the grid so that all of the numbers add up both horizontally and vertically:
Image

Unmarried males/Total Males = 13/20 = 65/100 = 65%.

The correct answer is D.
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by Santi » Wed Aug 10, 2011 8:22 pm
Thank you much for your reply!

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by Anamaiy » Wed Aug 10, 2011 10:32 pm
Hi,

With most percents problems I liked to insert the best consideration is 100:

SO if you consider a total of 100 subscriber then it follows

Male subscribers 20%= 20
Married Subscribers 70%=70
10% are married male, therefore 10% of 70 = 7
Hence not married males= 20-7 = 13
%age of male not married = 13/20= 65%

OA D