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 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.
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
06 Jul 2023, 01:31
Kudos
Bookmarks
D
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% (01:15) correct
20%
(01:58)
wrong
based on 144
sessions
History
Date
Time
Result
Not Attempted Yet
If machine A and machine B can finish the task in 4 hours when working together at their constant rates, in how many hours can machine B finish the task alone?
(1) Machine A can finish the task in 6 hours alone
(2) The hours that it takes machine B to finish the task alone is 6 hours longer than the hours that it takes machine A to finish the task alone
(1) Machine A can finish the task in 6 hours alone
(2) The hours that it takes machine B to finish the task alone is 6 hours longer than the hours that it takes machine A to finish the task alone
06 Jul 2023, 02:32
Kudos
Bookmarks
My Answer is D
1) Suff -
A can complete 1/6th of a task in an hour
1/6 + B = 1/4
Solve for B -> 12 hours
2) Suff -
A + B = 1/4 and B = A+6
1/x + 1/(x+6) = 1/4
Solve for x
x^2 - 2x - 24 = 0
(x-6)(x+4) = 0
x cant be negative
so x = 6. B takes 6 hours more than A. B takes 12 hours.
D
1) Suff -
A can complete 1/6th of a task in an hour
1/6 + B = 1/4
Solve for B -> 12 hours
2) Suff -
A + B = 1/4 and B = A+6
1/x + 1/(x+6) = 1/4
Solve for x
x^2 - 2x - 24 = 0
(x-6)(x+4) = 0
x cant be negative
so x = 6. B takes 6 hours more than A. B takes 12 hours.
D
07 Jul 2023, 01:49
Kudos
Bookmarks
Keep in mind that we only have to check whether question can be solved or not. We need not find exact answer. This will save tons of time in exam.
A and B's together working rate is known which is 1/4 task per hour (as in 4 hour, 1 unit of task is done). Following equation is valid for individual working rate:
\(\frac{1}{(A+B)} = \frac{1}{A} + \frac{1}{B}\)
Stmt 1: We now know A's working rate, which is 1/6 task per hour. So clearly B's working rate can be calculated hence sufficient.
Stmt 2: Difference between A and B's completion hour is given. So assume A takes x hours then B takes x+6 hours, again we have one equation and one variable hence sufficient.
Hence correct answer is D.
A and B's together working rate is known which is 1/4 task per hour (as in 4 hour, 1 unit of task is done). Following equation is valid for individual working rate:
\(\frac{1}{(A+B)} = \frac{1}{A} + \frac{1}{B}\)
Stmt 1: We now know A's working rate, which is 1/6 task per hour. So clearly B's working rate can be calculated hence sufficient.
Stmt 2: Difference between A and B's completion hour is given. So assume A takes x hours then B takes x+6 hours, again we have one equation and one variable hence sufficient.
Hence correct answer is D.
Bunuel
