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Hi mshrest01,
What is the source of this question?
This is clearly meant to be a "Work Formula" question, but it's terribly worded.
For reference, the work formula is:
(A)(B)/(A+B)
Thus, when you state that "worker A and B completes in 20 days", I assume this is meant to mean:
AB/(A+B) = 20
GMAT questions are always carefully worded to avoid biases or misunderstandings. This is NOT written in proper GMAT style.
GMAT assassins aren't born, they're made,
Rich
What is the source of this question?
This is clearly meant to be a "Work Formula" question, but it's terribly worded.
For reference, the work formula is:
(A)(B)/(A+B)
Thus, when you state that "worker A and B completes in 20 days", I assume this is meant to mean:
AB/(A+B) = 20
GMAT questions are always carefully worded to avoid biases or misunderstandings. This is NOT written in proper GMAT style.
GMAT assassins aren't born, they're made,
Rich
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GMATGuruNY
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I believe the intention of the problem is as follows:
Since A and B working together can do the job in 12 days, the combined rate for A and B = w/t = 48/12 = 4 pages per day.
Since B and C working together can do the job in 16 days, the combined rate for B and C = w/t = 48/16 = 3 pages per day.
Printer A worked for 5 days and printer B worked for 7 days:
Since A and B each worked for at least 5 days, the amount of work produced by A and B together over these 5 days = r*t = 4*5 = 20 pages.
Since B worked for 2 additional days, the amount of work produced by B and C together over these 2 days = r*t = 3*2 = 6 pages.
Remaining work = 48 - 20 - 6 = 22 pages.
Printer C worked for 13 days:
The work produced by C over 2 of these 13 days has already been counted, leaving 11 days for C to work alone.
Since C prints the remaining 22 pages over these 11 days, C's rate alone = w/t = 22/11 = 2 pages per day.
Thus:
Time for C to do the entire job on its own = w/r = 48/2 = 24 days.
Let the job = 48 pages.Working together, printers A and B can do a certain printing job in 12 days. Working together, printers B and C can do the job in 16 days. Over the past 13 days, printer A worked for 5 days, printer B worked for 7 days, and printer C worked for 13 days, with the result that the job was completed at the end of the 13 days. How many days would it take printer C to do the job on its own?
Since A and B working together can do the job in 12 days, the combined rate for A and B = w/t = 48/12 = 4 pages per day.
Since B and C working together can do the job in 16 days, the combined rate for B and C = w/t = 48/16 = 3 pages per day.
Printer A worked for 5 days and printer B worked for 7 days:
Since A and B each worked for at least 5 days, the amount of work produced by A and B together over these 5 days = r*t = 4*5 = 20 pages.
Since B worked for 2 additional days, the amount of work produced by B and C together over these 2 days = r*t = 3*2 = 6 pages.
Remaining work = 48 - 20 - 6 = 22 pages.
Printer C worked for 13 days:
The work produced by C over 2 of these 13 days has already been counted, leaving 11 days for C to work alone.
Since C prints the remaining 22 pages over these 11 days, C's rate alone = w/t = 22/11 = 2 pages per day.
Thus:
Time for C to do the entire job on its own = w/r = 48/2 = 24 days.
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
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ceilidh.erickson
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To reiterate Rich's point: do NOT study from non-GMAT-like sources! It will not help you to prepare for the test.
Please always post the source of your questions! Other students need to know which sources are good and which are not. You should always post the answer choices and OA as well.
Please always post the source of your questions! Other students need to know which sources are good and which are not. You should always post the answer choices and OA as well.
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
Yes thanks guys this was a tricky problem but u need to use algebrac manipulation.
Since it stated worker A worked for 5 days and worker B worked for 7 days and worker C worked for 13 days,
5A + 7B +13C= 1 work
Since A+ B together took 20 days their combined rates= (1/20)
Since B+C together took sixteen days their combined rates = (1/16)
From the earlier equation we can use distributive property
5(A+B)+ 2(B+C) +11C = 1 work
subsitute the rates into the equation R(A+B)=1/20 and R(B+C)=(1/16)
5(1/20) + 2(1/16)+11C= 1 work
1/4+1/8+11C=1 work
3/8+11C=1 work
11C=5/8
C=5/88
#of days C work= 1 work/rate of C=1/(5/88)=88/5=17.5 days=18days
Since it stated worker A worked for 5 days and worker B worked for 7 days and worker C worked for 13 days,
5A + 7B +13C= 1 work
Since A+ B together took 20 days their combined rates= (1/20)
Since B+C together took sixteen days their combined rates = (1/16)
From the earlier equation we can use distributive property
5(A+B)+ 2(B+C) +11C = 1 work
subsitute the rates into the equation R(A+B)=1/20 and R(B+C)=(1/16)
5(1/20) + 2(1/16)+11C= 1 work
1/4+1/8+11C=1 work
3/8+11C=1 work
11C=5/8
C=5/88
#of days C work= 1 work/rate of C=1/(5/88)=88/5=17.5 days=18days
