easy question from disclosure

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easy question from disclosure

by magical cook » Tue Sep 26, 2006 6:52 am
Please help someone who is good at math out there... thanks! Jane

q) In a marketing survey for products A,B and C, 1000 people were asked which of the products, if any, they use. The three circular regions in the diagram above represents the numbers of people who use products A, B and C, according to the survey results. Of the people surveyed, a total of 400 use A, a total of 400 use B, and a total of 450 use C.

What percent of the people surveyed use product A or product B or both, but not product C?

(See attached picture )

a) 12.5 %
b) 17.5%
c) 30%
d) 40%
e) 60%

The answer is C) but I dont know how to get there.... pls help!!
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by gamemaster » Tue Sep 26, 2006 12:44 pm
The number of people that use A or B is:

400+400 - 200 = 600

but, from them we need to decrease another 100+125+75 = 300 people

so we get 600-300 = 300

which are 30% from 1000

another way to solve it:

people who use ONLY A = 400 - (125+75+125) = 75
people who use ONLY B = 400 - (125+75+100) = 100

people who use A or B = 125

=> 300 use a or b or a+b

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by gamemaster » Tue Sep 26, 2006 12:46 pm
should be:

" people who use A or B but not C = 125 "

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Thank you gamemaster

by magical cook » Tue Sep 26, 2006 7:53 pm
Thank you, gamemaster

One question - is it okay to deduct the "75" part twice?

Thank you again for your help!
J.

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by gamemaster » Tue Sep 26, 2006 11:23 pm
Yes

Although i admit this drawing is very confusing, i think it would be more practical to stick to the numbers in this question

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Thanks!`

by magical cook » Tue Sep 26, 2006 11:39 pm
Okay, the, everything is cleared now. :)

By the way, the picture I drew is exactly the same on question on disclosure - I agree it's very confusing!!

Thanks again.
J.

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by minwu0529 » Sat Jan 19, 2013 6:38 pm
How to solve the third way.

The total number of people that use A ,B and C is ;

400+400+450-200-200-175+75= 750

but a total of 450 use C

The number of people that use A , or B is :

750-450 = 300