badar Posted August 31, 2006 Share Posted August 31, 2006 Hi all Please give a detail description of these 2 Gmat prep questions. D day in two day, desperation is sweeping me over Quote Link to comment Share on other sites More sharing options...
stucco005 Posted August 31, 2006 Share Posted August 31, 2006 In data suff questions, work out an equation or target the answer before diving into the additional data. 1. Let M = manager, D = director Needed: D/(D + M) (1) INSUFF, no information about D. (2) INSUFF, no information about M. (1) and (2): Setup and equation for the averages: 15000D + (-5000M)/[M+D] = 0 Note: use 0 as the average since the data specifies above and below. Solve to get: 1D to 3M, thus the percent of directors to managers is (1 director)/(4 total) 2. This is a Venn Diagram question, and is best solved by drawing such a diagram and filling in the values. An equation for this type of problem is: Total = All_Group1 + All_Group2 - Both + Neither. In this problem, the stem tells us that "each of the 128 people attended" so we can throw out the "Neither" portion of the formula above, and are left with: 128 = Morning_People + AfterNoon_People - Both. Now, the trick is to recognize that both the Morning_People value and the AfterNoon_People value contain the Both value. (That is why you must subtract the Both value so you can eliminate that value when the two Group values overlap). (1) INSUFF: Only tells you the Both parameter in the question. (2). SUFF: This tells you that: AfterNoon_People_ONLY + Both = (7/8), thus (1/8) = Morning_People_ONLY. So the answer is (1/8)128 Quote Link to comment Share on other sites More sharing options...
mmesarina Posted August 31, 2006 Share Posted August 31, 2006 In data suff questions, work out an equation or target the answer before diving into the additional data. 1. Let M = manager, D = director Needed: D/(D + M) (1) INSUFF, no information about D. (2) INSUFF, no information about M. (1) and (2): Setup and equation for the averages: 15000D + (-5000M)/[M+D] = 0 Note: use 0 as the average since the data specifies above and below. How did you came up with the equation above? I interpreted the statemnts as follows, where salary info is not given at all: 1) SMav = (SM + SD)/(M+D) - 5000 2) SDav = (SM+SD)/(M+D) + 15000 where SMav = avg salary of M SDav = avg salary of D SM = total salary of M SD = total salary of D Average salary of any employee is (SM+SD)/(M+D) There are too many unknowns, unless I am reading the stem wrong. Could you please explain your equation again? thanks Quote Link to comment Share on other sites More sharing options...
mukkimouse Posted August 31, 2006 Share Posted August 31, 2006 hi malina , even i agre with your point , in short , with the info given , we an nt reach the PERCENT OF DOCTORS , , STUCCO , pls advice , how did you arrived at the solution , thnx mouse Quote Link to comment Share on other sites More sharing options...
stucco005 Posted August 31, 2006 Share Posted August 31, 2006 hi malina , even i agre with your point , in short , with the info given , we an nt reach the PERCENT OF DOCTORS , , STUCCO , pls advice , how did you arrived at the solution , thnx mouse What if I asked you to find the average weight of 7 poeple, 5 of whom weigh an average of 175 lbs and the other 2 whom weigh an average of 300 lbs? How would you set up and solve that equation? Here's how: [5(175) + 2(300)]/7 = 1475/7 ~ 210 Now apply that same concept here: Let D = the number of directors. Likewise, let M = number of managers Let A = the average of salary of both D and M So, Using (1) and (2) together (and remembering the above example) we get: [(15000 + A)D + (A - 5000)M]/(D + M) = A 15000D + DA + MA - 5000M = DA + MA 15000D = 5000M 3D = M. So, remeber our original desire was to solve D/(D + M)? Then just substitue M for 3D and get D/(D + 3D) = D/4D = 1/4. Ans C. Quote Link to comment Share on other sites More sharing options...
mukkimouse Posted August 31, 2006 Share Posted August 31, 2006 BOSS PLS UNDERSTAND THAT , IN YOUR EXAMPLE TO ME , YOU ARE TALKING - WEIGHT * , WEIGHT --- , N WEIGHT -- What if I asked you to find the average weight of 7 poeple, 5 of whom weigh an average of 175 lbs and the other 2 whom weigh an average of 300 lbs? How would you set up and solve that equation? Here's how: [5(175) + 2(300)]/7 = 1475/7 ~ 210 CAN YOU CALCULATE THE AGE OF - DOCTORS , IN YOUR EXAMPLE , THIS IS MY POINT , YOU ARE MIXING VERIABALES , no of mangers -L , NO OF DOCS = G OK , AS PER ME THE EQN SHD BE - M1+ M2 + --- Ml / L = ( M1 +-----Ml) +( D1 +------+ Dg ) / L+g -5000 ---- ( EQN -1 ) D1+D2 +---- +Dg / g = ( M1 +-----Mp) +( D1 +------+ Dg ) / L+G +15000 -------------- ( eqn-2 ) or isthere anything wrong im doing here , --- can you pls solve this eqn for g / L+g == ? Now apply that same concept here: Quote Link to comment Share on other sites More sharing options...
mmesarina Posted August 31, 2006 Share Posted August 31, 2006 BOSS PLS UNDERSTAND THAT , IN YOUR EXAMPLE TO ME , YOU ARE TALKING - WEIGHT * , WEIGHT --- , N WEIGHT -- What if I asked you to find the average weight of 7 poeple, 5 of whom weigh an average of 175 lbs and the other 2 whom weigh an average of 300 lbs? How would you set up and solve that equation? Here's how: [5(175) + 2(300)]/7 = 1475/7 ~ 210 CAN YOU CALCULATE THE AGE OF - DOCTORS , IN YOUR EXAMPLE , THIS IS MY POINT , YOU ARE MIXING VERIABALES , no of mangers -L , NO OF DOCS = G OK , AS PER ME THE EQN SHD BE - M1+ M2 + --- Ml / L = ( M1 +-----Ml) +( D1 +------+ Dg ) / L+g -5000 ---- ( EQN -1 ) D1+D2 +---- +Dg / g = ( M1 +-----Mp) +( D1 +------+ Dg ) / L+G +15000 -------------- ( eqn-2 ) or isthere anything wrong im doing here , --- can you pls solve this eqn for g / L+g == ? Now apply that same concept here: Stucco is right and there is nothign wrong with your equation. What stucco is saying is that there is another equation that we did not consider: Equation A ) Average_salary_of_all = (Total_salary_of_doctors + Total_salary_of_managers) /(number_of_doctors + number_of_managers) A = (avrg_salary_doctor * D + avg_salary_manager * M) /M + D Stmt1) avrg_salary_doctor = Average_salary_of_all + 15000 = A + 15000 Stmt2) avrga_salary_manager = Average_salary_of_all - 5000 = A - 5000 Now replace avrg_salary_doctor and avg_salary_manager into Equation A A = ((A + 15000 ) *D + (A - 5000) * M)/ M + D A = (AD + 15000D + AM - 5000M )/ M + D AM + AD = AD + 15000D + AM - 5000M 15000D = 5000M M = 3D Replace in D / D + M and voila. Quote Link to comment Share on other sites More sharing options...
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