Last visit was: 06 Jun 2026, 11:17 It is currently 06 Jun 2026, 11:17
Home
Messages
MBA Fair
Tests
Schools
Events
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
   1   2   3 
User avatar
rahul16singh28
User avatar
Joined: 31 Jul 2017
Last visit: 09 Jun 2020
Posts: 428
Own Kudos:
505
 [1]
Given Kudos: 752
Location: Malaysia
Schools: INSEAD Jan '19
GPA: 3.95
WE:Consulting (Energy)
Schools: INSEAD Jan '19
Posts: 428
Kudos: 505
 [1]
3 cooks have to make 80 burgers.They are known to make 20 24 Jan 2018, 01:14
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
virtualanimosity
3 cooks have to make 80 burgers.They are known to make 20 pieces every minute working together.The 1st cook began workin alone and made 20 pieces having worked for sometime more than 3 mins.The remaining part of the work was done by second and 3rd cook working together.It took a total of 8 minutes to complete the 80 burgers.How many minutes would it take the 1st cook alone to cook 160 burgers?

A. 16 minutes
B. 24 mins
C. 32 mins
D. 40 mins
E. 30 mins
Show more

Let the time taken by A is \(t1 = \frac{20}{x}, t2 = \frac{60}{(y+z)}\)
Also, \(x + y + z = 20\)...
\(t1 + t2 = 80\), combing all the above equations we get \((x-10)(x-5) = 0\) or \(x =10, 5\)
But when we substitute \(x = 5\) in \(t1 = 20/x\) we get t1 = 2 but t1 is greater than 3, so \(t1 = 4\).
Hence, C.
User avatar
GMATinsight
User avatar
Major Poster
Joined: 08 Jul 2010
Last visit: 06 Jun 2026
Posts: 7,058
Own Kudos:
17,078
Given Kudos: 128
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Products:
My Reviews
Expert
Expert reply
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
Posts: 7,058
Kudos: 17,078
3 cooks have to make 80 burgers.They are known to make 20 13 Sep 2018, 21:06
Kudos
Add Kudos
Bookmarks
Bookmark this Post
virtualanimosity
3 cooks have to make 80 burgers.They are known to make 20 pieces every minute working together.The 1st cook began workin alone and made 20 pieces having worked for sometime more than 3 mins.The remaining part of the work was done by second and 3rd cook working together.It took a total of 8 minutes to complete the 80 burgers.How many minutes would it take the 1st cook alone to cook 160 burgers?

A. 16 minutes
B. 24 mins
C. 32 mins
D. 40 mins
E. 30 mins
Show more

a plane and very simple solution

Answer: Option C
Attachments

File comment: www.GMATinsight
Screen Shot 2018-09-14 at 9.35.05 AM.png
Screen Shot 2018-09-14 at 9.35.05 AM.png [ 458.89 KiB | Viewed 2649 times ]

User avatar
GMATinsight
User avatar
Major Poster
Joined: 08 Jul 2010
Last visit: 06 Jun 2026
Posts: 7,058
Own Kudos:
17,078
Given Kudos: 128
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Products:
My Reviews
Expert
Expert reply
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
Posts: 7,058
Kudos: 17,078
3 cooks have to make 80 burgers.They are known to make 20 13 Sep 2018, 21:08
Kudos
Add Kudos
Bookmarks
Bookmark this Post
virtualanimosity
3 cooks have to make 80 burgers.They are known to make 20 pieces every minute working together.The 1st cook began workin alone and made 20 pieces having worked for sometime more than 3 mins.The remaining part of the work was done by second and 3rd cook working together.It took a total of 8 minutes to complete the 80 burgers.How many minutes would it take the 1st cook alone to cook 160 burgers?

A. 16 minutes
B. 24 mins
C. 32 mins
D. 40 mins
E. 30 mins
Show more

Answer: Option C

Please check atachment for solution
Attachments

File comment: www.GMATinsight.com
Screen Shot 2018-09-14 at 9.35.05 AM.png
Screen Shot 2018-09-14 at 9.35.05 AM.png [ 458.89 KiB | Viewed 2635 times ]

User avatar
houston1980
User avatar
Joined: 30 May 2017
Last visit: 13 Dec 2025
Posts: 225
Own Kudos:
2,328
Given Kudos: 2,274
Location: United States
Schools: HBS '22
GMAT 1: 690 Q50 V33
GRE 1: Q168 V164
GPA: 3.57
Schools: HBS '22
GMAT 1: 690 Q50 V33
GRE 1: Q168 V164
Posts: 225
Kudos: 2,328
3 cooks have to make 80 burgers.They are known to make 20 10 Dec 2018, 10:25
Kudos
Add Kudos
Bookmarks
Bookmark this Post
virtualanimosity
3 cooks have to make 80 burgers.They are known to make 20 pieces every minute working together.The 1st cook began workin alone and made 20 pieces having worked for sometime more than 3 mins.The remaining part of the work was done by second and 3rd cook working together.It took a total of 8 minutes to complete the 80 burgers.How many minutes would it take the 1st cook alone to cook 160 burgers?

A. 16 minutes
B. 24 mins
C. 32 mins
D. 40 mins
E. 30 mins
Show more



I copied bml explanation to make the initial explanation easy for me houston1980.



bml
let the rates be x,y,z
\(\frac{20}{x+y+z} = 1\)
we know x+y+z = 20 and \(\frac{20}{x}+\frac{60}{y+z} = 8\)
putting (y+z) = (20-x) we get

\(x^2-15x+50=0\)
solving we get x= 5,10; x cannot be 10 because \(\frac{20}{x}>3\)

so to prepare 160 burgers, time reqd. = \(\frac{160}{5}=32\)

nice expl.n rohansherry
Show more
User avatar
RajatGMAT777
User avatar
Joined: 08 Oct 2020
Last visit: 12 Mar 2025
Posts: 30
Own Kudos:
19
Given Kudos: 28
Posts: 30
Kudos: 19
3 cooks have to make 80 burgers.They are known to make 20 24 Mar 2022, 09:13
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Armada0023
VeritasPrepKarishma

We know that the three together cook 20 burgers in 1 min i.e. we have their combined rate:
ra + rb + rc = 20 burgers/min

Also, they made 80 burgers in 8 mins such that:
\(\frac{20}{ra} + \frac{60}{(rb + rc)} = 8\)

Hi Karishma,
Thank you for the wonderful explanation. But, I do get lost when trying to follow how you were able to derive the above equation. Could you walk me through how you were able to set up: \(\frac{20}{ra} + \frac{60}{(rb + rc)} = 8\)?

Thank you!
Show more

Armada0023
These are simple Work Rate Equations. The rates of chef 3 chef's are ra, rb and rc respectively.
Also Time=work/rate
The work of 80 burgers is split as 20 burgers made by chef 1 alone with rate ra i.e. 20/ra
60 burgers made by chef 2 & 3 with combined rate of (rb+rc) i.e. 60/(rb + rc)
And given that it took total of 8 minutes t1+t2 = 8
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 39,186
Own Kudos:
1,128
Posts: 39,186
Kudos: 1,128
3 cooks have to make 80 burgers.They are known to make 20 30 Apr 2026, 06:24
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
   1   2   3 
Moderator:
Bunuel
Math Expert
111116 posts