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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 ## Jim can assemble b crates in an hour and Robert tagged by: M7MBA ##### This topic has 3 expert replies and 0 member replies ### Top Member ## Jim can assemble b crates in an hour and Robert Jim can assemble b crates in an hour and Robert can assemble 2b crates in an hour. Working together at this rate, how many crates can they assemble in four hours? A) 3b B) 6b C) 8b D) 12b E) 18b The OA is D. Which is the equation I should set to solve this PS question? Experts, may you give me some help, please? ### GMAT/MBA Expert GMAT Instructor Joined 08 Dec 2008 Posted: 13038 messages Followed by: 1251 members Upvotes: 5254 GMAT Score: 770 Top Reply M7MBA wrote: Jim can assemble b crates in an hour and Robert can assemble 2b crates in an hour. Working together at this rate, how many crates can they assemble in four hours? A) 3b B) 6b C) 8b D) 12b E) 18b We can also apply some logic to solve this question Given: Jim can assemble b crates in 1 hour So: Jim can assemble 2b crates in 2 hours [if we double the work time, we double the output] So: Jim can assemble 4b crates in 4 hours [if we double the work time (again), we double the output] Given: Robert can assemble 2b crates in 1 hour So: Robert can assemble 4b crates in 2 hours [if we double the work time, we double the output] So: Robert can assemble 8b crates in 4 hours [if we double the work time (again), we double the output] So, when we COMBINE their efforts, we add their 4-hour OUTPUTS That is, TOTAL output = color=red]4b[/color] + color=red]8b[/color] = 12b Answer: D Cheers, Brent _________________ Brent Hanneson â€“ Creator of GMATPrepNow.com Use my video course along with Sign up for free Question of the Day emails And check out all of these free resources GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMATâ€™s FREE 60-Day Study Guide and reach your target score in 2 months! ### GMAT/MBA Expert GMAT Instructor Joined 04 Oct 2017 Posted: 551 messages Followed by: 11 members Upvotes: 180 Quote: Jim can assemble b crates in an hour and Robert can assemble 2b crates in an hour. Working together at this rate, how many crates can they assemble in four hours? A) 3b B) 6b C) 8b D) 12b E) 18b The OA is D. Which is the equation I should set to solve this PS question? Experts, may you give me some help, please? Hi M7MBA, Let's take a look at your question. $$\text{Jim's rate }\ =\ \frac{b}{1}=b$$ $$\text{Robert's rate}\ =\ \frac{2b}{1}=2b$$ $$\text{Jim and Robert's combined rate}\ = b+2b=3b$$ Working together number of crates they assemble in 1 hour = 3b Working together number of crates they assemble in 4 hour = 3b * 4 = 12b Therefore, Option D is correct. Hope it helps. I am available if you'd like any follow up. _________________ GMAT Prep From The Economist We offer 70+ point score improvement money back guarantee. Our average student improves 98 points. Free 7-Day Test Prep with Economist GMAT Tutor - Receive free access to the top-rated GMAT prep course including a 1-on-1 strategy session, 2 full-length tests, and 5 ask-a-tutor messages. Get started now. ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10197 messages Followed by: 497 members Upvotes: 2867 GMAT Score: 800 Hi M7MBA, We're told that Jim can assemble B crates in an hour and Robert can assemble 2B crates in an hour. We're asked for the total number of crates that the two of them can assemble in four hours. This question can be solved Algebraically or by TESTing VALUES. Using Algebra, you know the number of crates assembled by the two people in 1 hour (B+2B = 3B per hour). Thus, over 4 hours, you have (4)(3B) = 12B crates TESTing VALUES, if... B = 2 Jim assembles 2 crates/hour Robert assembles 4 crates/hour Total = 6 crates an hour In 4 hours.... (4)(6) = 24 crates are assembled. Thus, we're looking for an answer that equals 24 when B=2. There's only one answer that matches. Final Answer: D GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com • FREE GMAT Exam Know how you'd score today for$0

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