Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Of the 300 patients who suffered from at least one symptom [#permalink]
17 May 2005, 07:20

1

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

(N/A)

Question Stats:

38% (02:15) correct
63% (02:35) wrong based on 5 sessions

Of the 300 patients who suffered from at least one symptom of A, B, and C, 35 % suffered from A, 45% suffered from B, 40 % suffered from C, 10% suffered from exactly 2 of them. How many people suffered from exactly one symptom?

(A intersect B) + (B intersect C) + (C intersect A) - (A intersect B intersect C) = 10%.300 = 30

T = A + B + C - (A inter B) - (B inter C) - (C inter A) + (A inter B inter C)
= A + B + C - 30 - 2 (A inter B inter C)
<--> 300 = 105 + 135 +120 - 30 - 2 (A inter B inter C)
--> (A inter B inter C) = 15

Christoph, are you assuming that nobody had all 3 symptoms?

i assume that 30 have exactly two symptoms and 30 have all three symptomps. A+B+C=360. so 30 have i.e. AB and 30 have ABC. so its A-ABC-AB+(B-ABC-AB)+(C-ABC)=105-30-30+135-30-30+120-30=210. is it ?

_________________

If your mind can conceive it and your heart can believe it, have faith that you can achieve it.

Please explain this problem ....I didnt get the solution.....

gmat, use Venn diagram, draw three intersecting circles representing A B C, there will be 3 areas where only to sets intersect, and 1 where all three intersect. Solution should be clear if you do that. Sorry I have no idea how to draw things on my comp, otherwise I would do it.

Re: PS - Venn Diag [#permalink]
24 Oct 2009, 22:47

pb_india wrote:

Of the 300 patients who suffered from at least one symptom of A, B, and C, 35 % suffered from A, 45% suffered from B, 40 % suffered from C, 10% suffered from exactly 2 of them. How many people suffered from exactly one symptom?

the trick here is to remember 4 main equations union of three sets = (sum of 3) - (sum of 2) + (all 3) exactly 2 = (sum of 2) - 3(all 3) at least 2 = (sum of 2) - 2(all 3) only 1 = (sum of 3) -2(sum of 2) + 3(all 3)

of course add neither to each one of these if not everyone is in a set...

Re: PS - Venn Diag [#permalink]
20 Aug 2010, 02:51

pb_india wrote:

Of the 300 patients who suffered from at least one symptom of A, B, and C, 35 % suffered from A, 45% suffered from B, 40 % suffered from C, 10% suffered from exactly 2 of them. How many people suffered from exactly one symptom?

Pls explain answer choice..

deferred solution till OA is out, but here it goes..

T = A + B + C - (2 of them) - 2 * (ABC) + neither

300 = 105 + 135 + 120 -30 -2*ABC

ABC = 15.

a + 2*b + 3*c = 105 + 135 + 120 = 360 a + 2*30 + 3*15 = 360

==> a = 255 pls explain the step in the red color

gmatclubot

Re: PS - Venn Diag
[#permalink]
20 Aug 2010, 02:51