Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2512:30 AM EDT
-01:30 AM EDT
At one point, she believed GMAT wasn’t for her. After scoring 595, self-doubt crept in and she questioned her potential. But instead of quitting, she made the right strategic changes. The result? A remarkable comeback to 695. Check out how Saakshi did it.
Apr 2610:00 AM EDT
-11:00 AM EDT
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
13 Feb 2020, 07:48
Kudos
Bookmarks
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
80% (01:09) correct
20%
(01:04)
wrong
based on 79
sessions
History
Date
Time
Result
Not Attempted Yet
Adam, Bob, Carol, Diane, and Ed are all sitting on a bench. If Adam and Diane must sit next to each other and Bob and Carol must sit next to each other, how many different seating arrangements are possible on the bench?
A) 3
B) 6
C) 8
D) 12
E) 24
A) 3
B) 6
C) 8
D) 12
E) 24
Updated on: 17 May 2021, 08:36
Originally posted by BrentGMATPrepNow on 13 Feb 2020, 08:01.
Last edited by BrentGMATPrepNow on 17 May 2021, 08:36, edited 1 time in total.
Last edited by BrentGMATPrepNow on 17 May 2021, 08:36, edited 1 time in total.
Kudos
Bookmarks
Bunuel
Take the task of arranging the people and break it into stages.
Important: Since Adam & Diane must sit next to each other, and since Bob & Carol must sit next to each other, let's "glue" them together to ensure that this happens.
Stage 1: "glue" Adam and Diane together
There are two different ways to glue these two people together: AD or DA.
So, we can complete stage 1 in 2 ways
Stage 2: "glue" Bob & Carol together
There are two different ways to glue these two people together: BC or CB.
So, we can complete stage 2 in 2 ways
At this point we have ensured that the two pairs of people must be next to each other.
We now have 3 "things" to arrange: Ed, the Adam/Diane pair, and the Bob/Carol pair.
Stage 3: Arrange the 3 "things"
We can arrange n unique objects in n! ways.
So we can arrange the 3 " things" in 3! ways (3! = 6)
So, we can complete stage 3 in 6 ways
By the Fundamental Counting Principle (FCP), we can complete all 3 stages (and thus arrange the 5 people) in (2)(2)(6) ways (= 24 ways)
Answer: E
Note: the FCP can be used to solve the MAJORITY of counting questions on the GMAT. So, be sure to learn it.
RELATED VIDEO
13 Feb 2020, 08:15
Kudos
Bookmarks
First, suppose A and D sit together, in the order AD, and B and C sit together in the order BC. We'd then be making a seating arrangement out of these three things: AD, BC, E. We'd be able to do that in 3! = 6 ways. But for A and D we have two choices -- they could be in the order AD or DA. We also have two choices for the order of B and C. Multiplying our choices, we thus have 6*2*2 = 24 possibilities in total.
