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• ### $450 Tuition Credit & Official CAT Packs FREE November 15, 2018 November 15, 2018 10:00 PM MST 11:00 PM MST EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth$100 with the 3 Month Pack ($299) • ### Free GMAT Strategy Webinar November 17, 2018 November 17, 2018 07:00 AM PST 09:00 AM PST Nov. 17, 7 AM PST. Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT. # A train travels from city A to city B. The average speed of the train  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Author Message TAGS: ### Hide Tags SVP Status: The Best Or Nothing Joined: 27 Dec 2012 Posts: 1827 Location: India Concentration: General Management, Technology WE: Information Technology (Computer Software) A train travels from city A to city B. The average speed of the train [#permalink] ### Show Tags 03 Nov 2014, 23:03 9 00:00 Difficulty: 55% (hard) Question Stats: 68% (02:47) correct 32% (02:38) wrong based on 205 sessions ### HideShow timer Statistics A train travels from city A to city B. The average speed of the train is 60 miles/hr and it travels the first quarter of the trip at a speed of 90 mi/hr. What is the speed of the train in the remaining trip? A. 30 B. 45 C. 54 D. 72 E. 90 _________________ Kindly press "+1 Kudos" to appreciate ##### Most Helpful Community Reply SVP Status: The Best Or Nothing Joined: 27 Dec 2012 Posts: 1827 Location: India Concentration: General Management, Technology WE: Information Technology (Computer Software) Re: A train travels from city A to city B. The average speed of the train [#permalink] ### Show Tags 10 Nov 2014, 19:00 5 2 Refer diagram below: Attachment: speed.png [ 3.39 KiB | Viewed 3992 times ] Setting up the time equation: Total time = Time required in first quarter + Time required in the remaining journey $$\frac{d}{60} = \frac{d}{4*90} + \frac{3d}{4*s}$$ $$s = \frac{90*3}{5} = 54$$ Answer = C _________________ Kindly press "+1 Kudos" to appreciate ##### General Discussion Senior Manager Status: Math is psycho-logical Joined: 07 Apr 2014 Posts: 422 Location: Netherlands GMAT Date: 02-11-2015 WE: Psychology and Counseling (Other) A train travels from city A to city B. The average speed of the train [#permalink] ### Show Tags 30 Jan 2015, 05:23 Using the RTD chart, with A being the first quarter, B the rest of the trip and All the combined "trip". _______R_____T______D A.........90........3..........270 B.........54.......15.........810 All........60.......18........1080 Let me explain how we fill in the chart: 1) Starting with what we know, we add 90 and 60 2) Picking an easy number for the total distance (6*9=54), so I chose 540. Multiply by 2 to get the whole trip, and we get 1080. Add 1080 for all-distance. 3) 1/4 of the whole distance happened at a Rate of 90. So, 1080/4=270, add 270 under A-D. 4) 2080 - 270 = 810, for the rest of the trip. Add 810 under B-D. 5) Claculate the individual Times for A and All, using T=D/R. Add the results, 3 and 18, under A-T and All-T. 6) 18-3=15, this is the remaining Time for B. Add 15 under B-T. 7) Finally, 15R=810 -->R=810/15 --> R= 54 ANS C Target Test Prep Representative Status: Founder & CEO Affiliations: Target Test Prep Joined: 14 Oct 2015 Posts: 4170 Location: United States (CA) Re: A train travels from city A to city B. The average speed of the train [#permalink] ### Show Tags 06 Apr 2017, 08:45 1 1 PareshGmat wrote: A train travels from city A to city B. The average speed of the train is 60 miles/hr and it travels the first quarter of the trip at a speed of 90 mi/hr. What is the speed of the train in the remaining trip? A. 30 B. 45 C. 54 D. 72 E. 90 We have an average rate problem in which we can use the following formula: Avg speed = (distance 1 + distance 2)/(time 1 + time 2) If we let d = total distance of the trip, then the first quarter of the trip, or (1/4)d = d/4, was traveled at 90 mph. Thus, the time was (d/4)/90 = d/360. We can let the rate for the remaining part of the trip = r, and thus the time for the remaining part of the trip, or (3/4)d = 3d/4, is (3d/4)/r = 3d/(4r). Let’s use all of this information in the average rate equation: 60 = d/(d/360 + 3d/(4r)) 60 = 1/(1/360 + 3/(4r)) 60(1/360 + 3/(4r)) = 1 1/6 + 45/r = 1 Let’s multiply the above equation by 6r: r + 270 = 6r 270 = 5r r = 54 Answer: C _________________ Scott Woodbury-Stewart Founder and CEO GMAT Quant Self-Study Course 500+ lessons 3000+ practice problems 800+ HD solutions EMPOWERgmat Instructor Status: GMAT Assassin/Co-Founder Affiliations: EMPOWERgmat Joined: 19 Dec 2014 Posts: 12853 Location: United States (CA) GMAT 1: 800 Q51 V49 GRE 1: Q170 V170 Re: A train travels from city A to city B. The average speed of the train [#permalink] ### Show Tags 08 Apr 2017, 17:53 2 Hi All, This question can be solved by TESTing VALUES. The prompt tells us that average speed of the train over the course of the entire trip is 60 miles/hr and that it travels the first quarter of the distance at a speed of 90 mi/hr. We're asked for the average speed of the train for the remaining three-quarters of the trip. Let's choose 90 miles for the FIRST QUARTER of the distance. We can then immediately calculate two things... 1) Since the train was traveling 90 miles/hour, the first quarter of the trip took 1 hour to complete. 2) Since (1/4)(Total Distance) = 90 miles, then the FULL TRIP = 4(90) = 360 miles. The total trip is 360 miles; with an average speed of 60 miles/hr, the FULL TRIP would take... (X)(60 mph) = 360 miles.... X = 6 hours to complete. The first hour of the trip covered 90 miles, so the remaining 360 - 90 = 270 miles of the trip are covered in the remaining 5 hours... Thus, the average speed for the remainder of the trip is... (270 miles)/(5 hours) = 54 miles/hour Final Answer: GMAT assassins aren't born, they're made, Rich _________________ 760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com # Rich Cohen Co-Founder & GMAT Assassin Special Offer: Save$75 + GMAT Club Tests Free
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Re: A train travels from city A to city B. The average speed of the train  [#permalink]

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29 Jul 2018, 06:25
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Re: A train travels from city A to city B. The average speed of the train &nbs [#permalink] 29 Jul 2018, 06:25
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