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100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote ## On a wedding catering service, An experienced chef can ##### This topic has 4 expert replies and 1 member reply ### Top Member ## On a wedding catering service, An experienced chef can ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult On a wedding catering service, An experienced chef can prepare a service for a wedding in 8 hours while an novice chef would finish the preparations in 12 hours. If the catering service employs the same number of novice and experienced chefs, then how many chefs would it take to prepare a wedding service in 1 hour and 36 minutes? (A) 2 (B) 3 (C) 4 (D) 6 (E) 8 OA D Source: Economist GMAT ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15254 messages Followed by: 1861 members Upvotes: 13060 GMAT Score: 790 Top Reply BTGmoderatorDC wrote: On a wedding catering service, An experienced chef can prepare a service for a wedding in 8 hours while an novice chef would finish the preparations in 12 hours. If the catering service employs the same number of novice and experienced chefs, then how many chefs would it take to prepare a wedding service in 1 hour and 36 minutes? (A) 2 (B) 3 (C) 4 (D) 6 (E) 8 Let service = 24 units. Rate for each experienced chef = w/t = 24/8 = 3 units per hour. Rate for each novice chef = w/t = 24/12 = 2 units per hour. Combined rate for 1 experienced chef and 1 novice chef working together = 3+2 = 5 units per hour. To produce 24 units in 1.6 hours, rate = w/t = 24/1.6 = 15 units per hour. Since each pair of chefs produces 5 units per hour, number of pairs needed = 15/5 = 3. Total number of chefs in 3 pairs = 2*3 = 6. The correct answer is D. _________________ Mitch Hunt Private Tutor for the GMAT and GRE GMATGuruNY@gmail.com If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon. Available for tutoring in NYC and long-distance. For more information, please email me at GMATGuruNY@gmail.com. Student Review #1 Student Review #2 Student Review #3 Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now. ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10124 messages Followed by: 494 members Upvotes: 2867 GMAT Score: 800 Top Reply Hi All, We're told that on a wedding catering service, an experienced chef can prepare a service for a wedding in 8 hours while an novice chef would finish the preparations in 12 hours. If the catering service employs the SAME number of novice and experienced chefs, then how many chefs would it take to prepare a wedding service in 1 hour and 36 minutes. This is an example of a Work Formula question and it can be solved in a couple of different ways. We can do a little math and take advantage of a 'rate shortcut' to save some calculation time. Work = (A)(B)/(A+B) where A and B are the individual times it takes two entities to complete a task IF.... we had just 1 experienced chef and just 1 novice chef, then the total time needed to prepare a service would be... (8)(12)/(8+12) = 96/20 = 4 4/5 hours = 4 hours 48 minutes IF... we DOUBLED the number of chefs, then the total time needed would be HALVED.... meaning that 2 experienced chefs and 2 novice chefs would need 2 hours 24 minutes. That's TOO SLOW though, so we need MORE chefs.... IF... we DOUBLED the number of chefs again, then the total time needed would be HALVED again.... meaning that 4 experienced chefs and 4 novice chefs would need 1 hour 12 minutes. That's TOO fast though, so we need LESS chefs... There's only one answer between 4 chefs and 8 chefs.... Final Answer: D GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com ### GMAT/MBA Expert GMAT Instructor Joined 09 Oct 2010 Posted: 1449 messages Followed by: 32 members Upvotes: 59 BTGmoderatorDC wrote: On a wedding catering service, An experienced chef can prepare a service for a wedding in 8 hours while an novice chef would finish the preparations in 12 hours. If the catering service employs the same number of novice and experienced chefs, then how many chefs would it take to prepare a wedding service in 1 hour and 36 minutes? (A) 2 (B) 3 (C) 4 (D) 6 (E) 8 Source: Economist GMAT Excellent opportunity for UNITS CONTROL, one of the most powerful tools of our method! $\left. \begin{gathered} {\text{N}}\,\,{\text{pros}}:\,\,\frac{{\,1 \cdot N\,\,{\text{services}}\,}}{{8\,\,{\text{hours}}}} = \frac{{\,\frac{N}{2}\,\,{\text{services}}\,}}{{4\,\,{\text{hours}}}}\,\,\,\,\,\, \hfill \\ {\text{N}}\,\,{\text{novs}}:\,\,\frac{{\,1 \cdot N\,\,{\text{services}}\,}}{{12\,\,{\text{hours}}}} = \frac{{\,\frac{N}{3}\,\,{\text{services}}\,}}{{4\,\,{\text{hours}}}} \hfill \\ \end{gathered} \right\}\,\,\,1\,\,{\text{service}}\,\,{\text{together}}\,\,{\text{in}}\,\,\,1{\text{h}}36\min \,\,\,\,;\,\,\,\,\,? = 2N$ $\left( {1 + \frac{{36}}{{60}}} \right)\,\,{\text{hours}}\,\,\,\left[ {\,\frac{{\,\left( {\frac{N}{2} + \frac{N}{3}} \right)\,\,{\text{services}}\,}}{{4\,\,{\text{hours}}}}\,} \right]\,\,\,\,\,\, = \,\,\,1\,\,\,{\text{service}}\,\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,\,\,\,\,\frac{{96}}{{60 \cdot 4}}\,\,\left( {\frac{{N \cdot \boxed3}}{{2 \cdot \boxed3}} + \frac{{N \cdot \boxed2}}{{3 \cdot \boxed2}}} \right)\,\,\, = \,\,\,1\,$ $\Rightarrow \,\,\,\,\,\,\frac{{24}}{{\,60\,}}\,\,\left( {\frac{{N \cdot \boxed3}}{{2 \cdot \boxed3}} + \frac{{N \cdot \boxed2}}{{3 \cdot \boxed2}}} \right)\,\,\, = \,\,\,1\,\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,\,\frac{{5N}}{6} = \frac{{60}}{{24}}\,\,\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,N = \frac{6}{5}\left( {\frac{{60}}{{24}}} \right) = 3\,\,\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,\,\,? = 2N = 6$ This solution follows the notations and rationale taught in the GMATH method. Regards, Fabio. _________________ Fabio Skilnik :: GMATH method creator ( Math for the GMAT) English-speakers :: https://www.gmath.net Portuguese-speakers :: https://www.gmath.com.br ### Top Member Legendary Member Joined 29 Oct 2017 Posted: 878 messages Followed by: 4 members Lets say, preparing a service for wedding is equivalent to 120units of work. (common multiple of 8 &12). Experienced chef will do = 15 units/hour Novice chef will do = 10 units/hour So, in one hour both will perform = 25units of work. If both of them work together then they will finish it in = 120/25 --> 4.8 hours, which is equivalent to 4 hours 48 minutes. 1E:1N= 4 hours 48 minutes 3E:3N= 1hour 36 minutes. Therefore, total chefs required 6. Regards! ### GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 2424 messages Followed by: 18 members Upvotes: 43 BTGmoderatorDC wrote: On a wedding catering service, An experienced chef can prepare a service for a wedding in 8 hours while an novice chef would finish the preparations in 12 hours. If the catering service employs the same number of novice and experienced chefs, then how many chefs would it take to prepare a wedding service in 1 hour and 36 minutes? (A) 2 (B) 3 (C) 4 (D) 6 (E) 8 The combined rate of one experienced chef and one novice chef is 1/8 + 1/12 = 3/24 + 2/24 = 5/24. Now let x = the number of chefs of each kind need to prepare the wedding service in 1 hour and 36 minutes or (60 + 36)/60 = 96/60 = 8/5 hours, we have: x * 5/24 * 8/5 = 1 x * 1/3 = 1 x = 3 Since 3 experienced chefs and 3 novice chefs are needed, a total of 6 chefs are needed for the wedding service. Answer: D _________________ Scott Woodbury-Stewart Founder and CEO scott@targettestprep.com See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. 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