Last visit was: 22 Apr 2026, 16:29 It is currently 22 Apr 2026, 16:29
Close
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

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
555-605 (Medium)|   Work and Rate Problems|                     
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 22 Apr 2026
Posts: 109,754
Own Kudos:
Given Kudos: 105,823
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,754
Kudos: 810,668
 [152]
5
Kudos
Add Kudos
147
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
PKN
Joined: 01 Oct 2017
Last visit: 11 Oct 2025
Posts: 809
Own Kudos:
1,636
 [47]
Given Kudos: 41
Status:Learning stage
WE:Supply Chain Management (Energy)
Posts: 809
Kudos: 1,636
 [47]
27
Kudos
Add Kudos
20
Bookmarks
Bookmark this Post
User avatar
MartyTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 24 Nov 2014
Last visit: 11 Aug 2023
Posts: 3,472
Own Kudos:
5,640
 [30]
Given Kudos: 1,430
Status:Chief Curriculum and Content Architect
Affiliations: Target Test Prep
GMAT 1: 800 Q51 V51
Expert
Expert reply
GMAT 1: 800 Q51 V51
Posts: 3,472
Kudos: 5,640
 [30]
19
Kudos
Add Kudos
11
Bookmarks
Bookmark this Post
General Discussion
avatar
redwood
Joined: 09 Jan 2019
Last visit: 24 Feb 2019
Posts: 2
Own Kudos:
3
 [3]
Given Kudos: 54
Posts: 2
Kudos: 3
 [3]
2
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
How did you transform \(\frac{1}{(r+3)}+\frac{1}{r}=\frac{1}{2}\) into \(r^2-r-6=0\) ? PKN :)
User avatar
PKN
Joined: 01 Oct 2017
Last visit: 11 Oct 2025
Posts: 809
Own Kudos:
1,636
 [4]
Given Kudos: 41
Status:Learning stage
WE:Supply Chain Management (Energy)
Posts: 809
Kudos: 1,636
 [4]
3
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
redwood
How did you transform \(\frac{1}{(r+3)}+\frac{1}{r}=\frac{1}{2}\) into \(r^2-r-6=0\) ? PKN :)

Hi redwood,
You must know the addition and subtraction of fractional expressions.

Here, \(\frac{1}{(r+3)}+\frac{1}{r}=\frac{1}{2}\)

Or, \(\frac{[1*r+1*(r+3)]}{(r+3)r}=\frac{1}{2}\)
Or, \(\frac{(2r+3)}{(r^2+3r)}=\frac{1}{2}\)
Cross-multiplying, We have
\(2(2r+3)=r^2+3r\)
Or, \(4r+6=r^2+3r\)
Or, \(r^2-r-6=0\)

Hope it helps.
avatar
redwood
Joined: 09 Jan 2019
Last visit: 24 Feb 2019
Posts: 2
Own Kudos:
Given Kudos: 54
Posts: 2
Kudos: 3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
PKN Thanks a lot, got it now! :)
avatar
abc11
Joined: 14 Sep 2018
Last visit: 15 Apr 2019
Posts: 10
Own Kudos:
5
 [3]
Given Kudos: 8
Posts: 10
Kudos: 5
 [3]
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Thanks. OG had a very confusing explanation. This is quite clear, and straightforward to follow.
avatar
pankajpaliitkgp
Joined: 04 Jun 2014
Last visit: 09 Jul 2020
Posts: 11
Own Kudos:
21
 [1]
Given Kudos: 16
Posts: 11
Kudos: 21
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi Marty,

I've solved this with similar logic and didn't solve the equation. Although, I knew that this equation will come out to be a quadratic which might have both imaginary roots or 2 positive roots.
So, my question is about the assumption that Gmat will give a true scenario in statements which will for sure have one positive root only that will be an answer. Thus, we don't need to check if the equation has only 1 positive root.
Please, let me know if this assumption is wrong.

Regards,
Pankaj

MartyTargetTestPrep
Bunuel
Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours. In how many hours can Rafael tabulate the data working alone?

(1) Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.
(2) Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.
Information given:

Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours.

Question:

In how many hours can Rafael tabulate the data working alone?

This question may seem complicated, but the truth is that since we know how long it takes for the two of them to complete the job, if we have any information that we can use to accurately compare how fast one works to how fast the other works, then we can answer the question.

Statement 1: Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.

We do not need to use any math to determine whether this statement is sufficient. We have only to notice that we know how long it takes for both of them to do the work together and that we have information that we can use to determine their relative speeds. With that information, we could work our way to the answer to the question, how many hours Rafael would take to do the job alone.

To see why, consider this:

Time for Rafael to do the job = R

Time for Salvador to do the job = R + 3

We are now working with one variable, and we have the time it takes for them to do the job together. So, we could work our way to Rafael's time.

Sufficient.

Statement 2: Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.

This tells us that Rafael works twice as fast as Salvador works. Since we know how long they take to do the job together, we can clearly work our way to Rafael's speed and then his time to do the job himself.

To see why, consider this:

Rafael's speed = 1/r

Salvador's speed = 1/2r

We are now working with one variable, and we have the time it takes for them to do the job together. So, we could work our way to Rafael's time, but we won't because this is a DS question.

Sufficient.

The correct answer is D.
User avatar
MartyTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 24 Nov 2014
Last visit: 11 Aug 2023
Posts: 3,472
Own Kudos:
5,640
 [2]
Given Kudos: 1,430
Status:Chief Curriculum and Content Architect
Affiliations: Target Test Prep
GMAT 1: 800 Q51 V51
Expert
Expert reply
GMAT 1: 800 Q51 V51
Posts: 3,472
Kudos: 5,640
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
pankajpaliitkgp
Hi Marty,

I've solved this with similar logic and didn't solve the equation. Although, I knew that this equation will come out to be a quadratic which might have both imaginary roots or 2 positive roots.
So, my question is about the assumption that Gmat will give a true scenario in statements which will for sure have one positive root only that will be an answer. Thus, we don't need to check if the equation has only 1 positive root.
Please, let me know if this assumption is wrong.

Regards,
Pankaj
Hi Pahkaj.

If a problem Solving question could be solved via the use of a quadratic, the solution will have only one root that works. Of course, Problem Solving questions have to work that way. Otherwise, they would not make sense, as a problem solving question has to have only one correct answer.

However, in answering a Data Sufficiency question, you can't assume that there will be only one root that works. It could be that there are multiple roots that work and that a statement or both statements are, therefore, insufficient.
User avatar
gmexamtaker1
Joined: 16 Jul 2018
Last visit: 13 Feb 2023
Posts: 208
Own Kudos:
80
 [2]
Given Kudos: 261
Products:
Posts: 208
Kudos: 80
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello guys ,
lets say time needed for Salvador=x and time needed for Rafael=x-3 so
1/x+1/x-3=1/2 solving this I get x^2-7x+6=0 so x could be 1 or 6 and we reject 1 because 1-3=negative number.
If I had chosen to set Rafael's time x and Salvador's x+3 i would end up with a quadratic that would give me one answer choice (with the first approach I almost lost the question because i thought that I had 2 valid options for A) . What I want to ask is the following, is there a way to choose beforehand the option that will require the least additional steps at least in this type of questions?
User avatar
dabaobao
Joined: 24 Oct 2016
Last visit: 20 Jun 2022
Posts: 541
Own Kudos:
Given Kudos: 143
GMAT 1: 670 Q46 V36
GMAT 2: 690 Q47 V38
GMAT 3: 690 Q48 V37
GMAT 4: 710 Q49 V38 (Online)
GMAT 4: 710 Q49 V38 (Online)
Posts: 541
Kudos: 1,697
Kudos
Add Kudos
Bookmarks
Bookmark this Post
MartyTargetTestPrep
Bunuel
Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours. In how many hours can Rafael tabulate the data working alone?

(1) Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.
(2) Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.
Information given:

Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours.

Question:

In how many hours can Rafael tabulate the data working alone?

This question may seem complicated, but the truth is that since we know how long it takes for the two of them to complete the job, if we have any information that we can use to accurately compare how fast one works to how fast the other works, then we can answer the question.

Statement 1: Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.

We do not need to use any math to determine whether this statement is sufficient. We have only to notice that we know how long it takes for both of them to do the work together and that we have information that we can use to determine their relative speeds. With that information, we could work our way to the answer to the question, how many hours Rafael would take to do the job alone.

To see why, consider this:

Time for Rafael to do the job = R

Time for Salvador to do the job = R + 3

We are now working with one variable, and we have the time it takes for them to do the job together. So, we could work our way to Rafael's time.

Sufficient.

Statement 2: Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.

This tells us that Rafael works twice as fast as Salvador works. Since we know how long they take to do the job together, we can clearly work our way to Rafael's speed and then his time to do the job himself.

To see why, consider this:

Rafael's speed = 1/r

Salvador's speed = 1/2r

We are now working with one variable, and we have the time it takes for them to do the job together. So, we could work our way to Rafael's time, but we won't because this is a DS question.

Sufficient.

The correct answer is D.

MartyTargetTestPrep How can we tell that we'll have just have 1 positive value and not 2 positive values from statement 1 without forming the quadratic and doing the steps shown below?

1/R + 1/(R+3) = 1/2
(R+3 + R)/(R(R+3)) = 1/2
4R + 6 = R^2 + 3R
R^2 - R - 6 = 0
No need to solve further since C is negative, implying we'll have 2 roots: one + and one -. Since only + value is allowed, sufficient.
User avatar
MartyTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 24 Nov 2014
Last visit: 11 Aug 2023
Posts: 3,472
Own Kudos:
5,640
 [6]
Given Kudos: 1,430
Status:Chief Curriculum and Content Architect
Affiliations: Target Test Prep
GMAT 1: 800 Q51 V51
Expert
Expert reply
GMAT 1: 800 Q51 V51
Posts: 3,472
Kudos: 5,640
 [6]
6
Kudos
Add Kudos
Bookmarks
Bookmark this Post
dabaobao
MartyTargetTestPrep
Bunuel
Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours. In how many hours can Rafael tabulate the data working alone?

(1) Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.
(2) Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.
Information given:

Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours.

Question:

In how many hours can Rafael tabulate the data working alone?

This question may seem complicated, but the truth is that since we know how long it takes for the two of them to complete the job, if we have any information that we can use to accurately compare how fast one works to how fast the other works, then we can answer the question.

Statement 1: Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.

We do not need to use any math to determine whether this statement is sufficient. We have only to notice that we know how long it takes for both of them to do the work together and that we have information that we can use to determine their relative speeds. With that information, we could work our way to the answer to the question, how many hours Rafael would take to do the job alone.

To see why, consider this:

Time for Rafael to do the job = R

Time for Salvador to do the job = R + 3

We are now working with one variable, and we have the time it takes for them to do the job together. So, we could work our way to Rafael's time.

Sufficient.

Statement 2: Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.

This tells us that Rafael works twice as fast as Salvador works. Since we know how long they take to do the job together, we can clearly work our way to Rafael's speed and then his time to do the job himself.

To see why, consider this:

Rafael's speed = 1/r

Salvador's speed = 1/2r

We are now working with one variable, and we have the time it takes for them to do the job together. So, we could work our way to Rafael's time, but we won't because this is a DS question.

Sufficient.

The correct answer is D.

MartyTargetTestPrep How can we tell that we'll have just have 1 positive value and not 2 positive values from statement 1 without forming the quadratic and doing the steps shown below?

1/R + 1/(R+3) = 1/2
(R+3 + R)/(R(R+3)) = 1/2
4R + 6 = R^2 + 3R
R^2 - R - 6 = 0
No need to solve further since C is negative, implying we'll have 2 roots: one + and one -. Since only + value is allowed, sufficient.
Logic dictates that, if we have the length of time it takes for them to complete the task working together and also information that we can use to determine their relative rates, only one result is possible. There is no way in which the information provided could generate two rates.

Think about it. If we have the time it takes for them to do the job together, and we know that one is faster than the other, and we know how much faster, we at that point know that only one rate set of rates will work. There's just no way that there would be two different results. How would there be more than one? The relative rates have been defined and the total rate has been defined. There's only one way in which all are going to work with each other.
User avatar
Basshead
Joined: 09 Jan 2020
Last visit: 07 Feb 2024
Posts: 907
Own Kudos:
Given Kudos: 431
Location: United States
Posts: 907
Kudos: 323
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Question: To fill an order, a manufacturer had to produce 1000 tools per day for n days. what is the value of n?

Lets take a look at the statements:

(1) Because of production problems, the manufacturer produced only 600 tools per day during the first 5 days

600 * 5 = 3000 tools

We know the manufacturer needed to produce 5,000 tools; thus, the manufacturer was 2,000 tools short over the span of the first 5 days. However, we can't determine the value of n. Insufficient.

(2) Because of production problems, the manufacturer had to produce 1,500 tools per day on each of the last 4 days in order to meet the schedule

1,500 * 4 = 6,000

We know the manufacturer needed to produce 4,000 tools over the span of 4 days; thus, the manufacturer produced 2,000 more tools to compensate for earlier days. However, we still can't determine the value of n. Insufficient.

(1&2) From the two statements combined, we know the manufacturer made 9,000 tools. However, we still don't know the number of days the manufacturer worked. There could have been days where the manufacturer made 1,000 tools a day. We can only conclude that the manufacturer worked at least 9 days. Insufficient.

Answer is E.
User avatar
MHIKER
Joined: 14 Jul 2010
Last visit: 24 May 2021
Posts: 939
Own Kudos:
5,811
 [1]
Given Kudos: 690
Status:No dream is too large, no dreamer is too small
Concentration: Accounting
Posts: 939
Kudos: 5,811
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours. In how many hours can Rafael tabulate the data working alone?

(1) Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.
(2) Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.


NEW question from GMAT® Quantitative Review 2019


(DS13907)

They both do in 1 hour =1/2 job

(1) Rafael does in \(x\) hours, then Salvador does \(x+ 3;\) So, \(\frac{1}{x}+\frac{1}{x+3}=\frac{1}{2};\) Sufficient.

(2) Rafael x, Salvador 2x, So, \(\frac{1}{x}+\frac{1}{2x}=\frac{1}{2}\) Sufficient.

The answer is \(D\)
User avatar
jabhatta2
Joined: 15 Dec 2016
Last visit: 21 Apr 2023
Posts: 1,251
Own Kudos:
Given Kudos: 188
Posts: 1,251
Kudos: 328
Kudos
Add Kudos
Bookmarks
Bookmark this Post
MartyTargetTestPrep
Statement 1: Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.

We do not need to use any math to determine whether this statement is sufficient. We have only to notice that we know how long it takes for both of them to do the work together and that we have information that we can use to determine their relative speeds. With that information, we could work our way to the answer to the question, how many hours Rafael would take to do the job alone.

To see why, consider this:

Time for Rafael to do the job = R

Time for Salvador to do the job = R + 3

We are now working with one variable, and we have the time it takes for them to do the job together. So, we could work our way to Rafael's time.

Sufficient.


Hi MartyTargetTestPrep - For S1 - You mention, just because there is one variable, you know this statement is sufficient (without pen to paper and no math calculation)

If the Rafael time's is t and Salvador's time is t+3 for example

How are you so sure - there is only ONE value of T and not multiple values of T ?

T after all does not have an integer constraint and can be any positive value over zero.
User avatar
MartyTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 24 Nov 2014
Last visit: 11 Aug 2023
Posts: 3,472
Own Kudos:
5,640
 [1]
Given Kudos: 1,430
Status:Chief Curriculum and Content Architect
Affiliations: Target Test Prep
GMAT 1: 800 Q51 V51
Expert
Expert reply
GMAT 1: 800 Q51 V51
Posts: 3,472
Kudos: 5,640
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
jabhatta2
MartyTargetTestPrep
Statement 1: Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.

We do not need to use any math to determine whether this statement is sufficient. We have only to notice that we know how long it takes for both of them to do the work together and that we have information that we can use to determine their relative speeds. With that information, we could work our way to the answer to the question, how many hours Rafael would take to do the job alone.

To see why, consider this:

Time for Rafael to do the job = R

Time for Salvador to do the job = R + 3

We are now working with one variable, and we have the time it takes for them to do the job together. So, we could work our way to Rafael's time.

Sufficient.


Hi MartyTargetTestPrep - For S1 - You mention, just because there is one variable, you know this statement is sufficient (without pen to paper and no math calculation)

If the Rafael time's is t and Salvador's time is t+3 for example

How are you so sure - there is only ONE value of T and not multiple values of T ?

T after all does not have an integer constraint and can be any positive value over zero.
Think about it.

If Rafael's rate is 1/T and Salvadore's rate is 1/(T + 3), and they are both postiive and must add up to 1/2, how would there be different postiive numbers that would work?

We also know at this point that Rafael's rate is greater since 1/T > 1/(T+3).

Without calculating the rates, we can see that there is specific relationship between them. Only one set up numbers will add up to 1/2 and fit those other constraints.
User avatar
Vegita
Joined: 23 May 2020
Last visit: 08 Sep 2025
Posts: 85
Own Kudos:
Given Kudos: 1,528
Posts: 85
Kudos: 12
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi MartyTargetTestPrep

The equation that I got from the question stem is (R+S) * 2 = 1, in which I assumed R and S to be the rates of Rafael and Salvador.

Can you please help me understand how people are getting 1/R + 1/S = 1/2? I think I have a conceptual gap here.
User avatar
MartyTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 24 Nov 2014
Last visit: 11 Aug 2023
Posts: 3,472
Own Kudos:
5,640
 [1]
Given Kudos: 1,430
Status:Chief Curriculum and Content Architect
Affiliations: Target Test Prep
GMAT 1: 800 Q51 V51
Expert
Expert reply
GMAT 1: 800 Q51 V51
Posts: 3,472
Kudos: 5,640
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Vegita
Hi MartyTargetTestPrep

The equation that I got from the question stem is (R+S) * 2 = 1, in which I assumed R and S to be the rates of Rafael and Salvador.
That equation makes sense, since the question says, "Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours."

Quote:
Can you please help me understand how people are getting 1/R + 1/S = 1/2? I think I have a conceptual gap here.
The R and S in that equation are not their rates. They are the numbers of hours they take to complete the job alone.

So, in that equation, 1/R is Rafael's rate alone, and 1/S is Salvador's rate alone, which add up to 1/2, since together they take two hours to tabulate one set.
User avatar
Elite097
Joined: 20 Apr 2022
Last visit: 04 Feb 2026
Posts: 739
Own Kudos:
Given Kudos: 346
Location: India
GPA: 3.64
Posts: 739
Kudos: 568
Kudos
Add Kudos
Bookmarks
Bookmark this Post
gmexamtaker1
Hello guys ,
lets say time needed for Salvador=x and time needed for Rafael=x-3 so
1/x+1/x-3=1/2 solving this I get x^2-7x+6=0 so x could be 1 or 6 and we reject 1 because 1-3=negative number.
If I had chosen to set Rafael's time x and Salvador's x+3 i would end up with a quadratic that would give me one answer choice (with the first approach I almost lost the question because i thought that I had 2 valid options for A) . What I want to ask is the following, is there a way to choose beforehand the option that will require the least additional steps at least in this type of questions?
ThatDudeKnows avigutman I have the same doubt. MartyTargetTestPrep
User avatar
avigutman
Joined: 17 Jul 2019
Last visit: 30 Sep 2025
Posts: 1,285
Own Kudos:
1,906
 [3]
Given Kudos: 66
Location: Canada
GMAT 1: 780 Q51 V45
GMAT 2: 780 Q50 V47
GMAT 3: 770 Q50 V45
Expert
Expert reply
GMAT 3: 770 Q50 V45
Posts: 1,285
Kudos: 1,906
 [3]
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Elite097
gmexamtaker1
Hello guys ,
lets say time needed for Salvador=x and time needed for Rafael=x-3 so
1/x+1/x-3=1/2 solving this I get x^2-7x+6=0 so x could be 1 or 6 and we reject 1 because 1-3=negative number.
If I had chosen to set Rafael's time x and Salvador's x+3 i would end up with a quadratic that would give me one answer choice (with the first approach I almost lost the question because i thought that I had 2 valid options for A) . What I want to ask is the following, is there a way to choose beforehand the option that will require the least additional steps at least in this type of questions?
ThatDudeKnows avigutman I have the same doubt. MartyTargetTestPrep
gmexamtaker1 and Elite097 no, I can't think of a way to know ahead of time whether it's better to go with x & (x+3) or (x-3) & x.
Having said that, in my humble opinion we shouldn't put pen to paper at all for this question. In a 2-minute-per-question kind of test, this question should be solved conceptually. We know how long the job takes them together, and with statement (1) on its own, if we were to draw a number line, we could plot the amounts of time each would take on his own as two tick marks with 3 hours in between. The question is, essentially, can those two tick marks be moved up or down the number line without changing the amount of time they take to do the job together (since that's already given)? The answer is no: if we push the tick marks to the right, the job is going to take them longer if they were to work together, and vice versa if we push the tick marks to the left. Therefore, knowing the delta in their individual times is sufficient to answer the question.
I would evaluate statement (2) conceptually as well. If you find yourself building a quadratic equation on the GMAT, it's likely that you're doing something inappropriate.
 1   2   
Moderators:
Math Expert
109754 posts
498 posts
212 posts