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.
Sep 2807:00 PM EDT
-10:00 PM EDT
Boost your GMAT score in less than one month in a live online class + 6 months access to TTP OnDemand video courses included! Class starts Mon, Tues, Wed, Thur, Fri Sept. 28, 2026 - Oct. 16, 2027, 7:00pm-10:00pm EST
Sep 2911:00 AM EDT
-01:00 PM EDT
" Description: Top scores are possible when you enroll in a powerful GMAT course, taught live online + 6 months access to TTP OnDemand video courses included! Class starts Tues/Thur Sept. 29, 2026 - Dec. 3, 2026, 11:00am-1:00pm EST
Oct 0107:00 AM BST
-08:00 AM GMT
Welcome to the GMAT Club's Free Interview Prep Event for Top MBA Programs! Buy tickets - Virtual series that’s all set to equip you to -excel in your MBA interviews.
Oct 0301:00 PM EDT
-04:00 PM EDT
Top scores are possible when you enroll in a powerful GMAT course, taught live online + 6 months access to TTP OnDemand video courses included! Class starts Saturdays Oct. 3, 2026 - Dec. 26, 2026, 1:00pm-4:00pm EST
14 Jan 2025, 15:06
Kudos
Bookmarks
The number of jobs
completed by machine J: 63 The number of jobs completed by
machines K and L working together
and with no other machines: 42
completed by machine J: 63 The number of jobs completed by
machines K and L working together
and with no other machines: 42
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
85%
(hard)
Question Stats:
62% (03:10) correct
38%
(03:08)
wrong
based on 1047
sessions
History
Date
Time
Result
Not Attempted Yet
Working together, machine J, machine K, and machine L can complete a job in 12 minutes. Working alone, machine J can complete a job in 20 minutes. Machine J worked alone for a given amount of time. Then, machines K and L worked together, and with no other machine, for the same amount of time.
In the table below, select two numbers that are consistent with the information that is given. In the first column, select the row that shows the number of jobs completed by machine J working alone, and in the second column, select the row that shows the number of jobs completed by machines K and L working together and with no other machines. Make exactly one selection for each column.
In the table below, select two numbers that are consistent with the information that is given. In the first column, select the row that shows the number of jobs completed by machine J working alone, and in the second column, select the row that shows the number of jobs completed by machines K and L working together and with no other machines. Make exactly one selection for each column.
|
The number of jobs completed by machine J |
The number of jobs completed by machines K and L working together and with no other machines |
|
| 24 | ||
| 42 | ||
| 60 | ||
| 63 | ||
| 84 | ||
| 96 |
ShowHide Answer
Official Answer
The number of jobs
completed by machine J: 63 The number of jobs completed by
machines K and L working together
and with no other machines: 42
completed by machine J: 63 The number of jobs completed by
machines K and L working together
and with no other machines: 42
15 Jan 2025, 07:00
Kudos
Bookmarks
1. Let the speeds of the three machines be j, k, and l.
2. All three machines do one job for 12 minutes: j + k + l = 1/12.
3. Machine J does one job in 20 minutes, or j = 1/20.
4. The number of jobs completed by machine J is \(j * t = \frac{1}{20} * t = \frac{t}{20}\) and the number of jobs completed by machines K and L working together and with no other machines is \((k + l) * t = (\frac{1}{12} - j) * t = \frac{1}{30} * t = \frac{t}{30}\).
5. The ratio between the two numbers is \(\frac{\frac{t}{20}}{\frac{t}{30}} = \frac{3}{2}\).
6. Out of all the answer choices, only the pair 63 and 42 have this ratio.
7. Our answer will be: The number of jobs completed by machine J - 63 and The number of jobs completed by machines K and L working together and with no other machines - 42.
2. All three machines do one job for 12 minutes: j + k + l = 1/12.
3. Machine J does one job in 20 minutes, or j = 1/20.
4. The number of jobs completed by machine J is \(j * t = \frac{1}{20} * t = \frac{t}{20}\) and the number of jobs completed by machines K and L working together and with no other machines is \((k + l) * t = (\frac{1}{12} - j) * t = \frac{1}{30} * t = \frac{t}{30}\).
5. The ratio between the two numbers is \(\frac{\frac{t}{20}}{\frac{t}{30}} = \frac{3}{2}\).
6. Out of all the answer choices, only the pair 63 and 42 have this ratio.
7. Our answer will be: The number of jobs completed by machine J - 63 and The number of jobs completed by machines K and L working together and with no other machines - 42.
General Discussion
14 Jan 2025, 22:46
Kudos
Bookmarks
Rate of Work of Machine J = 1/20.
Rate of Work of Machines K+L = 1/12-1/20=1/30.
Now both machines work for the same time.
Hence We need to assume the Work done by J alone, then reverse calculate the time taken, then find out if corresponding work done for K+L is present in the options or not.
Eg:
Checking for 24(for J)
For J to have done 24 units of work, Total time was 24(1/20)=24*20
Therefore for K+L total work done would be = 24*20*1/30 = 16 (Not available)
Check for 63 (for J)
Total Time allocated was 63/(1/20)=63*20
Work done by K+L = 63*20/30= 42
Rate of Work of Machines K+L = 1/12-1/20=1/30.
Now both machines work for the same time.
Hence We need to assume the Work done by J alone, then reverse calculate the time taken, then find out if corresponding work done for K+L is present in the options or not.
Eg:
Checking for 24(for J)
For J to have done 24 units of work, Total time was 24(1/20)=24*20
Therefore for K+L total work done would be = 24*20*1/30 = 16 (Not available)
Check for 63 (for J)
Total Time allocated was 63/(1/20)=63*20
Work done by K+L = 63*20/30= 42
