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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 ## Algebra tagged by: BTGmoderatorRO ##### This topic has 1 expert reply and 0 member replies ## Algebra It takes 30 days to fill a laboratory dish with bacteria. If the size of the bacteria doubles each day, how long did it take for the bacteria to fill one half of dish? A) 10 days B) 15 days C) 24 days D) 29 days E) 29.5 days OA is d It's a simple problem here but I am struggling to express what happens here algebraically. Please help me ### GMAT/MBA Expert GMAT Instructor Joined 04 Oct 2017 Posted: 551 messages Followed by: 11 members Upvotes: 180 Hello Roland. I hope I can clarify it to you. You can establish a function that represents the growth of bacteria as follows: $$f\left(t\right)=2^t$$ where t is the number of days. If it takes 30 days to fill a laboratory dish it implies that the capacity of the laboratory dish is $$f\left(30\right)=2^{30}.$$ The half of the capacity is $$\frac{2^{30}}{2}=2^{29}.$$ Note that this final result is equal to f(29). So, the half of the laboratory dish is filled after 29 days, The correct answer is D. I'm available if you'd like any follow up. Regards. _________________ 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. • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • Free Practice Test & Review How would you score if you took the GMAT Available with Beat the GMAT members only code • FREE GMAT Exam Know how you'd score today for$0

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