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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 Each Machine of type A has 3 steel parts and 2 chrome parts. tagged by: BTGmoderatorLU This topic has 3 expert replies and 0 member replies Top Member Each Machine of type A has 3 steel parts and 2 chrome parts. Timer 00:00 Your Answer A B C D E Global Stats Difficult Source: GMAT Paper Tests Each Machine of type A has 3 steel parts and 2 chrome parts. Each machine of type B has 4 steel parts and 7 chrome parts. If a certain group of type A and type B machines has a total of 20 steel parts and 22 chrome parts, how many machines are in the group A. 2 B. 3 C. 4 D. 6 E. 9 The OA is D. GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15348 messages Followed by: 1864 members Upvotes: 13060 GMAT Score: 790 BTGmoderatorLU wrote: Source: GMAT Paper Tests Each Machine of type A has 3 steel parts and 2 chrome parts. Each machine of type B has 4 steel parts and 7 chrome parts. If a certain group of type A and type B machines has a total of 20 steel parts and 22 chrome parts, how many machines are in the group A. 2 B. 3 C. 4 D. 6 E. 9 (3 steel parts in each type A machine) + (4 steel parts in each type B machine) = 20 steel parts: 3A + 4B = 20 3A = a multiple of 3 less than 20. Options for 3A: 3, 6, 9, 12, 15, 18 4B = a multiple of 4 less than 20. Options for 4B: 4, 8, 12, 16 Only the two values in blue yield a sum of 20. Thus: 3A = 12, implying that A=4 4B = 8, implying that B=2 A+B = 4+2 = 6 The correct answer is D. _________________ 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! Sign up now. GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10197 messages Followed by: 496 members Upvotes: 2867 GMAT Score: 800 Hi All, We're told that each Machine of type A has 3 steel parts and 2 chrome parts, each machine of type B has 4 steel parts and 7 chrome parts and a certain group of type A and type B machines has a total of 20 steel parts and 22 chrome parts. We're asked for the total number of machines. This question can be approached in a number of different ways; the easiest approach would likely be to focus on the 'multiples' involved and play around a little bit with the basic Arithmetic. While it might seem a bit weird, we can actually ignore whether the parts are 'steel' or 'chrome.' Each Machine A has a total of 5 parts and each Machine B has a total of 11 parts. The 'group' has a total of 42 parts, so we need to add a multiple of 5 to a multiple of 11 and end up with 42. The number 42 is relatively small, so there's likely just one way to get to that total... You might recognize that 11(2) = 22... meaning that there would be 42 - 22 = 20 parts remaining. Since 20 is a multiple of 5, we know that there would be 4 type B machines to go along with the 2 Type A machines. That's the only way to get to 42 total parts, so 4+2 = 6 must be the answer. Final Answer: D GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 2791 messages Followed by: 18 members Upvotes: 43 BTGmoderatorLU wrote: Source: GMAT Paper Tests Each Machine of type A has 3 steel parts and 2 chrome parts. Each machine of type B has 4 steel parts and 7 chrome parts. If a certain group of type A and type B machines has a total of 20 steel parts and 22 chrome parts, how many machines are in the group A. 2 B. 3 C. 4 D. 6 E. 9 The OA is D. We can let a = the number of type A machines and b = the number of type B machines; thus: 3a + 4b = 20 (This is the equation for the steel parts.) and 2a + 7b = 22 (This is the equation for the chrome parts.) Multiplying the first equation by -2 and the second by 3, we have: -6a - 8b = -40 and 6a + 21b = 66 Adding the equations together, we are left with: 13b = 26 b = 2, so a is: 3a + 4 x 2 = 20 3a = 12 a = 4 So there are 6 machines. Answer: D _________________ 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 • FREE GMAT Exam Know how you'd score today for$0

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