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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 ## A certain hotel has 1,400 single rooms and 420 double rooms. tagged by: AAPL ##### This topic has 3 expert replies and 0 member replies ### Top Member ## A certain hotel has 1,400 single rooms and 420 double rooms. ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult GMAT Paper Tests A certain hotel has 1,400 single rooms and 420 double rooms. Each room is cleaned by one person. If one person can clean a single room every 15 minutes and a double room every 20 minutes, how many cleaning persons are needed to clean all the rooms if each person works for exactly 7 hours? A. 65 B. 70 C. 80 D. 90 E. 265 OA B ### GMAT/MBA Expert GMAT Instructor Joined 08 Dec 2008 Posted: 12827 messages Followed by: 1247 members Upvotes: 5254 GMAT Score: 770 AAPL wrote: GMAT Paper Tests A certain hotel has 1,400 single rooms and 420 double rooms. Each room is cleaned by one person. If one person can clean a single room every 15 minutes and a double room every 20 minutes, how many cleaning persons are needed to clean all the rooms if each person works for exactly 7 hours? A. 65 B. 70 C. 80 D. 90 E. 265 OA B The hotel has 1,400 single rooms, and one person can clean a single room every 15 minutes So, one person can clean 4 single rooms in ONE HOUR In other words, it takes 1 WORKER HOUR to clean 4 single rooms 1400/4 = 350 So, it takes 350 WORKER HOURS to clean 1400 rooms The hotel has 420 double rooms, and one person can clean a double room every 20 minutes So, one person can clean 3 double rooms in ONE HOUR In other words, it takes 1 WORKER HOUR to clean 3 double rooms 420/3 = 140 So, it takes 140 WORKER HOURS to clean 420 double rooms How many cleaning persons are needed to clean all the rooms if each person works for exactly 7 hours? 350 + 140 = 490 So, 490 WORKER HOURS are required to clean ALL of the room. 490/7 = 70. So, 70 workers are needed. Answer: B Cheers, Brent _________________ Brent Hanneson â€“ Creator of GMATPrepNow.com Use our video course along with Sign up for our free Question of the Day emails And check out all of our 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 25 Apr 2015 Posted: 2424 messages Followed by: 18 members Upvotes: 43 AAPL wrote: GMAT Paper Tests A certain hotel has 1,400 single rooms and 420 double rooms. Each room is cleaned by one person. If one person can clean a single room every 15 minutes and a double room every 20 minutes, how many cleaning persons are needed to clean all the rooms if each person works for exactly 7 hours? A. 65 B. 70 C. 80 D. 90 E. 265 OA B It takes 1400 x 1/4 = 350 hours to clean the single rooms and 420 x 1/3 = 140 hours to clean the double rooms, for a total time of 490 hours. We can let n = the number of workers and create the equation: 7n = 490 n = 70 Answer: B _________________ 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. Read our reviews ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10124 messages Followed by: 494 members Upvotes: 2867 GMAT Score: 800 Hi camitava, This is essentially a rate question. Here's how to solve it: Single rooms take one person 15 minutes to clean and double rooms take one person 20 minutes to clean. 15 mins. = 1/4 hour 20 mins. = 1/3 hour With 1400 single rooms x 1/4 hour = 350 hours of total work for 1 person With 420 double rooms x 1/3 hour = 140 hours of total work for 1 person For ALL the rooms, we have a total of 350 + 140 = 490 hours of total work for 1 person To get the work done in 7 hours, we'll need 490/7 = 70 workers Final Answer: B GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Award-winning private GMAT tutoring Register now and save up to$200

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