Of 30 snakes at the reptile house, 10 have stripes, 21 are poisonous, and 5 have no stripes and are not poisonous. How many of the snakes have stripes AND are poisonous?
A. 4
B. 6
C. 9
D. 15
E. 20
OA B
Source: Manhattan Prep
Of 30 snakes at the reptile house, 10 have stripes, 21 are
This topic has expert replies
-
- Moderator
- Posts: 7187
- Joined: Thu Sep 07, 2017 4:43 pm
- Followed by:23 members
GMAT/MBA Expert
- Jay@ManhattanReview
- GMAT Instructor
- Posts: 3008
- Joined: Mon Aug 22, 2016 6:19 am
- Location: Grand Central / New York
- Thanked: 470 times
- Followed by:34 members
Given that there are 5 snakes that have no stripes and are not poisonous, there are 30 - 5 = 25 snakes that either have stripes or are poisonous.BTGmoderatorDC wrote:Of 30 snakes at the reptile house, 10 have stripes, 21 are poisonous, and 5 have no stripes and are not poisonous. How many of the snakes have stripes AND are poisonous?
A. 4
B. 6
C. 9
D. 15
E. 20
OA B
Source: Manhattan Prep
Say,
there are x snakes that have stripes and are poisonous. Thus,
there are (10 - x) snakes that have stripes but are not poisonous, and
there are (21 - x) snakes that are poisonous but do not have stripes.
=> 25 = (21 - x) + (10 - x) + x
=> x = 6
The correct answer: B
Hope this helps!
-Jay
_________________
Manhattan Review GRE Prep
Locations: GRE Classes Ho Chi Minh City | GRE Prep Course Kuala Lumpur | GRE Prep Shanghai | SAT Prep Course Hong Kong | and many more...
Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Total \(= a +b -\) both \(+\) neitherBTGmoderatorDC wrote:Of 30 snakes at the reptile house, 10 have stripes, 21 are poisonous, and 5 have no stripes and are not poisonous. How many of the snakes have stripes AND are poisonous?
A. 4
B. 6
C. 9
D. 15
E. 20
OA B
Source: Manhattan Prep
\(30= 10 + 21 - x + 5\)
\(x = 6\). Answer B
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7245
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
We can create the equation:BTGmoderatorDC wrote:Of 30 snakes at the reptile house, 10 have stripes, 21 are poisonous, and 5 have no stripes and are not poisonous. How many of the snakes have stripes AND are poisonous?
A. 4
B. 6
C. 9
D. 15
E. 20
OA B
Source: Manhattan Prep
Total = #Stripes + #Poisonous - Both + Neither
30 = 10 + 21 - Both + 5
30 = 36 - Both
Both = 6
Answer: B
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews