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.
Nov 1912:30 PM EST
-01:30 PM EST
Learn how Keshav, a Chartered Accountant, scored an impressive 705 on GMAT in just 30 days with GMATWhiz's expert guidance. In this video, he shares preparation tips and strategies that worked for him, including the mock, time management, and more
Nov 2001:30 PM EST
-02:30 PM IST
Learn how Kamakshi achieved a GMAT 675 with an impressive 96th %ile in Data Insights. Discover the unique methods and exam strategies that helped her excel in DI along with other sections for a balanced and high score.
Nov 2211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Nov 23
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Nov 2407:00 PM PST
-08:00 PM PST
Full-length FE mock with insightful analytics, weakness diagnosis, and video explanations!
Nov 2510:00 AM EST
-11:00 AM EST
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.
23 Jul 2021, 03:26
Kudos
Bookmarks
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
66% (02:19) correct
34%
(02:26)
wrong
based on 223
sessions
History
Date
Time
Result
Not Attempted Yet
A can do a piece of work in 12 days. B can do this work in 16 days. A started the work alone. After how many days should B join him, so that the work is finished in 9 days?
A. 2 days
B. 3 days
C. 4 days
D. 5 days
E. 1 day
A. 2 days
B. 3 days
C. 4 days
D. 5 days
E. 1 day
23 Jul 2021, 04:36
Kudos
Bookmarks
rajatchopra1994
A is working continuously when they finish the job in 9 days, so A alone will complete 9/12, or 3/4 of the job. So all we need to know is how long it would take B to do the rest, or 1/4 of the job, and since B does the whole job in 16 days, B does 1/4 of the job in 4 days. So we need B to work for the last 4 days out of the 9 total days, and B should thus join after 5 days.
General Discussion
23 Jul 2021, 04:08
Kudos
Bookmarks
Solution:
Let us assume the work to be done \(= 48\) (LCM of 12 and 16)
We are given A can do this work in \(12\) days. Thus the rate at which A works \(= R_{A} = \frac{48}{12} = 4\)
We are given B can do this work in \(16\) days. Thus the rate at which B works \(= R_{B} = \frac{48}{16} = 3\)
So the rate at which they work when working together \(= R_{A} + R_{A} = 4+3=7\)
We are given that \(A\) worked for some days before \(B\) joins and the work gets completed in \(9\) days
Let us assume that \(A\) works for \(n\) number of days alone before \(B\) joins. So we can make the WRT table as:
WRT.png [ 4.35 KiB | Viewed 8457 times ]
We know total work \(= 48\)
\(⇒ 4n+63-7n=48\)
\(⇒ 63-3n=48\)
\(⇒ 3n=15\)
\(⇒ n=5\)
Hence the right answer is Option D.
Let us assume the work to be done \(= 48\) (LCM of 12 and 16)
We are given A can do this work in \(12\) days. Thus the rate at which A works \(= R_{A} = \frac{48}{12} = 4\)
We are given B can do this work in \(16\) days. Thus the rate at which B works \(= R_{B} = \frac{48}{16} = 3\)
So the rate at which they work when working together \(= R_{A} + R_{A} = 4+3=7\)
We are given that \(A\) worked for some days before \(B\) joins and the work gets completed in \(9\) days
Let us assume that \(A\) works for \(n\) number of days alone before \(B\) joins. So we can make the WRT table as:
Attachment:
WRT.png [ 4.35 KiB | Viewed 8457 times ]
We know total work \(= 48\)
\(⇒ 4n+63-7n=48\)
\(⇒ 63-3n=48\)
\(⇒ 3n=15\)
\(⇒ n=5\)
Hence the right answer is Option D.
