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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 ## At Supersonic Corporation, the time required for a machine tagged by: BTGmoderatorLU ##### This topic has 1 member reply ### Top Member ## At Supersonic Corporation, the time required for a machine ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult Source: Manhattan Prep At Supersonic Corporation, the time required to complete a job is determined by the formula: $$t=\sqrt{w}+\sqrt{(w-1)},$$ where w = the weight of the machine in pounds and t = the hours required to complete the job. If machine A weighs 8 pounds, and machine B weighs 7 pounds, how many hours will it take the two machines to finish one job if they work together? $$\text{A. }\frac{6}{7-\sqrt{3}}$$ $$\text{B. }\frac{1}{2}(\sqrt{8}+\sqrt{6})$$ $$\text{C. }\frac{1}{3}(6-\sqrt{3})$$ $$\text{D. }3(\sqrt{3}+\sqrt{2})$$ $$\text{E. }\sqrt{8}+2\sqrt{7}+\sqrt{6}$$ The OA is B Junior | Next Rank: 30 Posts Joined 03 Oct 2018 Posted: 10 messages t1= $$\sqrt{8}+\sqrt{7}\$$ t2= $$\sqrt{7\ }+\sqrt{6}$$ 1/t=(1/t1)+(1/t2) Before plugging in the values, its more efficient to rationalize the values here itself. So t1 becomes $$\sqrt{8\ }-\sqrt{7}$$ and t2= $$\sqrt{7}-\sqrt{6}$$. t=1/ $$\sqrt{8}-\sqrt{6}$$ Now rationalizing this value we get t= $$\frac{\sqrt{8}+\sqrt{6}}{2}$$ • FREE GMAT Exam Know how you'd score today for$0

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