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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 Gunther, the pizza delivery boy, went out from the store tagged by: BTGmoderatorLU This topic has 2 expert replies and 0 member replies Top Member Gunther, the pizza delivery boy, went out from the store Timer 00:00 Your Answer A B C D E Global Stats Difficult Source: e-GMAT Gunther, the pizza delivery boy, went out from the store carrying pizzas to deliver for the residents in 3 housing societies named Hufflepuff, Ravenclaw, and Slytherin. He started at 6:30 pm from the shop at a speed of 15 mph. After 15 minutes he reached Hufflepuff Society, and it took 15 minutes to deliver all pizzas there. Then at the same speed he moved for another 15 minutes to reach Ravenclaw, and in 15 minutes delivered all pizza. Finally, he drove towards Slytherin at double of his original speed, and after reaching there in 15 minutes time, he realised that the order has been cancelled. What is Gunther’s average speed in this whole journey (time includes delivery time)? A. 8 mph B. 10 mph C. 12 mph D. 15 mph E. 30 mph The OA is C. GMAT/MBA Expert GMAT Instructor Joined 22 Aug 2016 Posted: 1770 messages Followed by: 28 members Upvotes: 470 BTGmoderatorLU wrote: Source: e-GMAT Gunther, the pizza delivery boy, went out from the store carrying pizzas to deliver for the residents in 3 housing societies named Hufflepuff, Ravenclaw, and Slytherin. He started at 6:30 pm from the shop at a speed of 15 mph. After 15 minutes he reached Hufflepuff Society, and it took 15 minutes to deliver all pizzas there. Then at the same speed he moved for another 15 minutes to reach Ravenclaw, and in 15 minutes delivered all pizza. Finally, he drove towards Slytherin at double of his original speed, and after reaching there in 15 minutes time, he realised that the order has been cancelled. What is Gunther’s average speed in this whole journey (time includes delivery time)? A. 8 mph B. 10 mph C. 12 mph D. 15 mph E. 30 mph The OA is C. > Time taken to reach Hufflepuff Society = 15 minutes > Time taken to deliver Pizzas at Hufflepuff Society = 15 minutes > Time taken to reach Ravenclaw Society = 15 minutes > Time taken to deliver Pizzas at Ravenclaw Society = 15 minutes > Time taken to reach Slytherin Society = 15 minutes Total time taken = 5 * 15 = 75 minutes = 1.25 hours > Distance traveled to reach Hufflepuff Society driving @ 15 mph for 15 minutes = 15/4 miles > Distance traveled to reach Ravenclaw Society driving @ 15 mph for 15 minutes = 15/4 miles > Distance traveled to reach Slytherin Society driving @ 30 mph for 15 minutes = 15/2 miles Total distance travelled = 15/4 + 15/4 + 15/2 = 15 miles Average speed = Total distance traveled / Total time taken = 15 / 1.25 = 12 mph The correct answer: C Hope this helps! -Jay _________________ Manhattan Review GRE Prep Locations: GRE Classes Miami | GRE Prep Course Munich | GRE Prep Denver | LSAT Prep Course Orlando | and many more... Schedule your free consultation with an experienced GMAT Prep Advisor! Click here. GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15105 messages Followed by: 1859 members Upvotes: 13060 GMAT Score: 790 BTGmoderatorLU wrote: Source: e-GMAT Gunther, the pizza delivery boy, went out from the store carrying pizzas to deliver for the residents in 3 housing societies named Hufflepuff, Ravenclaw, and Slytherin. He started at 6:30 pm from the shop at a speed of 15 mph. After 15 minutes he reached Hufflepuff Society, and it took 15 minutes to deliver all pizzas there. Then at the same speed he moved for another 15 minutes to reach Ravenclaw, and in 15 minutes delivered all pizza. Finally, he drove towards Slytherin at double of his original speed, and after reaching there in 15 minutes time, he realised that the order has been cancelled. What is Gunther’s average speed in this whole journey (time includes delivery time)? A. 8 mph B. 10 mph C. 12 mph D. 15 mph E. 30 mph Average = sum/quantity. In this case: Average speed = (sum of the minutes spent at each speed)/(total number of minutes). Total time spent at 15mph = 30 minutes. Total time spent delivering pizzas at 0mph = 30 minutes. Total time spent at 30mph = 15 minutes. Average speed = (15*30 + 0*30 + 30*15)/(30 + 30 + 15) = 900/75 = 300/25 = 60/5 = 12. The correct answer is C. _________________ 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! 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