BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Overlapping Method

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 41
Joined: Mon Mar 01, 2010 5:57 pm
Location: US
Thanked: 1 times
GMAT Score:640

Overlapping Method

by 2011mbaspirant » Wed Mar 03, 2010 6:23 pm
Can some one please help me understand the following type of questions.

In the Kan film festival, 50 movies were presented. 3/5 are action and 4/5 are science fiction. How many movies were science fiction action movies?
a) 10
b) 15
c) 20
d) 30
e) 35

Per the manual the correct answer is C.

I am finding such problem difficult to crack.
Thanks for your time and help.
Top
Source: — Problem Solving |
User avatar
Community Manager
Posts: 1537
Joined: Mon Aug 10, 2009 6:10 pm
Thanked: 653 times
Followed by:252 members

by papgust » Wed Mar 03, 2010 6:29 pm
It's a simple venn diagram problem.

Total movies = 50

Action movies = 3/5 * 50 = 30
Science fiction = 4/5 * 50 = 40
Both Action and science fiction = 'x'

Total movies = Action movies + Science fiction - Both
50 = 30+40-x
[spoiler]x = 20[/spoiler]
Top
Master | Next Rank: 500 Posts
Posts: 487
Joined: Fri Mar 27, 2009 5:49 am
Thanked: 36 times

by dtweah » Sun Mar 07, 2010 6:57 am
Here is one intuitive way. Draw your ven diagram of A and S and put X at the intersection.
Now if 3/5 are action movies, then 2/5 are NOT action movie or are ONLY Science moivies. PUt 2/5 in in the only Science portion. ( This area is the complement of A).

But u are told All of S is 4/5.

So total S is

X + 2/5 = 4/5

X = 2/5

2/5 x 50 = 20.
Top
Post new topic Post Reply
• Page 1 of 1