Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 02 Jul 2015, 16:19

### GMAT Club Daily Prep

#### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# I need someone to come up with the formula to this problem.

Author Message
TAGS:
Eternal Intern
Joined: 07 Jun 2003
Posts: 468
Location: Lone Star State
Followers: 1

Kudos [?]: 47 [0], given: 0

I need someone to come up with the formula to this problem.  [#permalink]  22 Jul 2003, 09:55
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
I need someone to come up with the formula to this problem.

In a certain survery of a group of people, 87 people said they found Americans the sexiest, 91 indicated they found Indians the sexiest, and 91 indicated they found Russians the sexiest. Of the people surveyed 9 liked only Americans, 10 liked only Indians, 12 liked only Russians, and 40 liked all three types of girls. How many of the people surveyed liked both Indians and Russians but not American girls?
Manager
Joined: 10 Jun 2003
Posts: 210
Location: Maryland
Followers: 2

Kudos [?]: 4 [0], given: 0

Venn [#permalink]  22 Jul 2003, 10:11
Draw a venn (or store a picture in your head) and you get the following three equations...

Let Indian & Russian = X
Let Indian & American = Y
Let Russian & American = Z

X + Y = 41
Y + Z = 38
X + Z = 39

Solve away and you get

X = 21
Y = 20
Z = 18

I quickly plugged back in these #'s and they added up - just to check it!!

Answering the question, the girls in question are represented by X, and therefore 21 is the answer.
(time to complete was 1:35)
Eternal Intern
Joined: 07 Jun 2003
Posts: 468
Location: Lone Star State
Followers: 1

Kudos [?]: 47 [0], given: 0

Explain how you came up with equations.

I have no clue and can't follow.
Manager
Joined: 10 Jun 2003
Posts: 210
Location: Maryland
Followers: 2

Kudos [?]: 4 [0], given: 0

Draw the picture [#permalink]  22 Jul 2003, 12:45
Draw the Venn diagram and it will be clear. Remember that the original numbers that you gave total in each of the nationality "circles". Example: Americans ONLY + Americans & Russians + Americans & Indians + all three = 87. After considering all of the information given, all we need to do is find Americans & Russians, Americans & Indians, and Indians & Russians. Look at the Venn and see what needs to add up. From that we got the three equations with three variables.
Eternal Intern
Joined: 07 Jun 2003
Posts: 468
Location: Lone Star State
Followers: 1

Kudos [?]: 47 [0], given: 0

But it's just not Americans only; thanks, Mciatto little shaky on venns.
Victor
Manager
Joined: 22 Jul 2003
Posts: 62
Location: CA
Followers: 1

Kudos [?]: 0 [0], given: 0

IS = Set representing people who believe Indians are the sexiest = 91
RS= Set representing people who believe Russians are the sexiest = 91
AS= Set representing people who believe Americans are the sexiest = 87

LOI=subset for people who like only Indian girls = 10
LOR=subset for people who like only Russian girls = 12
LOA=subset for people who like only American girls = 9

IRA= people who like all 3 = 40

IR = people liking Indian and Russian girls = x
IA = people liking Indian and American girls = y
RA= people liking Russian and American girls = z

So, from the Venn diagram,

For the circle representing Indians,
x + y + 40 = IS - LOI
=> x + y + 40 = 91 – 10
=> x + y = 41

Similarly, we will get,
y + z = 38
x + z = 39

Now, solving for x will get us 21.

P.S. In the original question, I read "sexiest" as "sexist" and was thinking in the line that if some people think that "Indians are sexist" then they will not like "Indian girls" etc. Sometimes my own carelessness amazes me.
_________________

P K Das

Eternal Intern
Joined: 07 Jun 2003
Posts: 468
Location: Lone Star State
Followers: 1

Kudos [?]: 47 [0], given: 0

Dog [#permalink]  23 Jul 2003, 09:26

Can't you use the easy way?

Manager
Joined: 22 Jul 2003
Posts: 62
Location: CA
Followers: 1

Kudos [?]: 0 [0], given: 0

This is the Venn diagram which explains how Stolyar got the 3 equations. I did not solve them again. Thanks
_________________

P K Das

Founder
Affiliations: AS - Gold, UA - Silver, HH-Diamond
Joined: 04 Dec 2002
Posts: 12821
Location: United States (WA)
GMAT 1: 750 Q49 V42
GPA: 3.5
WE: Information Technology (Hospitality and Tourism)
Followers: 2725

Kudos [?]: 13517 [0], given: 3865

Expert's post
WOW, very impressive Diagram.

Pracuda, you are either a math expert or an artist
Similar topics Replies Last post
Similar
Topics:
3 Word Problem, formulas 4 04 Aug 2010, 03:03
1 Can someone explain this problem to me? 8 15 Mar 2009, 18:53
What is the probability of having a coin come up heads at 5 21 Aug 2006, 08:39
Anyone have the correct formula for this problem? It almost 2 02 Aug 2006, 19:41
Display posts from previous: Sort by