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Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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08 Jul 2011, 18:40
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Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together? A. 20% B. 30% C. 40% D. 50% E. 60%
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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08 Jul 2011, 19:34
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Pat can do the Job alone in 1/(1/3  1/5) = 1/2/15 hrs = 7.5 hrs So in 3 hrs, Pat does 3/7.5 * 100 % = 1000/25 = 40% Answer  C
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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10 Jul 2011, 21:53
weird, i was getting D (50%) Subbed in 30 for work done then backsolved and got the same time for Y, therefore 50%. I didn't understand your method subhashgosh, could you pls explains how you got the first equation. Thanks!
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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11 Jul 2011, 00:44
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subhashghosh wrote: Pat can do the Job alone in 1/(1/3  1/5) = 1/2/15 hrs = 7.5 hrs
So in 3 hrs, Pat does 3/7.5 * 100 % = 1000/25 = 40%
Answer  C A bit different. I used formula 1/t1+1/t2=1/T Thus => 1/5 + 1/x (Pet) = 1/3 => 1/5 + 2/15(Pet)= 1/3 => 2/15 div 1/3 = 40%



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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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11 Jul 2011, 02:58
Ok, that makes sense too. Thanks Izvos!
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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11 Jul 2011, 03:37
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Sal: 1/5 in 1 hour Sal: 3/5 in 3 hours
Therefore, pat has done 2/5 = 40% of the job.
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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11 Jul 2011, 03:49
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bschool83 wrote: Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?
A. 20% B. 30% C. 40% D. 50% E. 60% You can also use ratios to get the answer in under 10 secs. Time taken together : Time taken by Sal = 3:5 Rate of work together : Rate of work of Sal = 5:3 So out of 5, Sal does 3 parts of the job and Pat does 2 parts. 2/5 is 40%. For more on ratios: http://www.veritasprep.com/blog/2011/03 ... ofratios/http://www.veritasprep.com/blog/2011/03 ... osintsd/http://www.veritasprep.com/blog/2011/03 ... problems/
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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11 Jul 2011, 03:57
Pike and veritias. Liked your approach. Saves a lot of time!!!



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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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28 Jul 2011, 21:43
Could one of you help me solve this question, based on both Carishma's ratio method and the regular "inverse of time to get the rate" method? I got the answer, but intuitively, and was unable to set up the final equation to determine % contribution to work: Working alone at its own constant rate, a machine seals k cartons in 8 hours, and working alone at its own constant rate, a 2nd machine seals k cartons in 4 hours. If the two machines, each working at its own constant rate and for the same period of time, together sealed a certain number of cartons, what % of the cartons were sealed by the machine working at the faster rate? a) 25% b) 33 1/3% c) 50% d) 66 2/3% e) 75% Scroll down for the answer
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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28 Jul 2011, 22:47
ok worked on it a bit more, if you take the rate of the 2nd machine and divide it by the calculated combined rate, it gives you the % contribution to overall work by that machine: k/43k/8 =2/3 (or 66.66%) or D
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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21 Aug 2011, 11:05
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pal would take = 3*5/2 = 15/2 hrs to complete the job OR pal in 1hr can do 2/15 of the job in 3 hr pal will do 6/15 = 2/5 of the job 2/5 of the job OR 40%
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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21 Aug 2011, 18:28
1/5 + 1/p = 1/3 => p = 15/2
=> pat can do the work 1 alone in 15/2 hours = > pats rate = 2/15
amount of work done by pat in 3 hours = (2/15)*3 = 2/5
i.e ((2/5)/1)*100 = 40%



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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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02 Feb 2017, 03:08
1) First we need to find Sal's and Pat's rates: Rate of Sal and Pat working together: \(\frac{1}{3}\) Rate of Sal: \(\frac{1}{5}\) Rate of Pat: \(\frac{1}{3}\)\(\frac{1}{5}=\frac{2}{15}\) 2) Now we can compare rate's of Sal and Pat: \(\frac{1}{5} vs. \frac{2}{15}; \frac{3}{15} vs. \frac{2}{15}\) While Pat does 2 segments of work, Sal does 3. This means that when the job id done, Pat has completed 40% of work.
The correct answer is C.



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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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02 Feb 2017, 10:39
bschool83 wrote: Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?
A. 20% B. 30% C. 40% D. 50% E. 60% Let the total work be 15 units (S + P )'s efficiency / hr is 5 units/hr S's efficiency / hr is 3 units/hr So, P's efficiency / hr is 2 units/hr So, P does 2/5*100 => 40% job.... Answer will be (C) 40%
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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02 Feb 2017, 11:42
bschool83 wrote: Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?
A. 20% B. 30% C. 40% D. 50% E. 60% Sal's percent of job=(1/5)/(1/3)=3/5=60% Pat's percent of job=10060=40%



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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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05 Feb 2017, 18:35
Rate of Sal & Pat together = 1\3 Rate of Sal = 1\5 Rate of Pat = 1\3  1\5 = 2\15 Total work done by Pat = 2\15 * 3 = 2\5 = 40%



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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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08 Feb 2017, 10:21
bschool83 wrote: Sal and Pat can finish a job together in 3 hours. If Sal can do the job alone in 5 hours, what percent of the job does Pat do when Sal and Pat finish the entire job together?
A. 20% B. 30% C. 40% D. 50% E. 60% We are given that Sal and Pat, working together, can complete a job in 3 hours. Since rate = work/time, the combined rate of Sal and Pat is 1/3. We are also given that Sal can complete the job alone is 5 hours; thus he has a rate of 1/5. Since Sal’s rate + Pat’s rate = the combined rate, Pat’s rate = the combined rate  Sal’s rate. That is, Pat’s rate = 1/3  1/5 = 5/15  3/15 = 2/15. Thus, when the job is completed, Pat completes (2/15)(3) = 6/15 = 2/5 = 0.4 = 40% of the job. Answer: C
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Re: Sal and Pat can finish a job together in 3 hours. If Sal can do the jo [#permalink]
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26 Mar 2017, 12:04
1) Assume total work = 30 (e.g., cars)
2) Sal: Work=30 cars Time alone=5 hours Speed=30/5=6 cars/hour Work done in 3 hours (that he works together with Pat)=6*3=18 cars (out of 30 cars)=60%
3) Pat Work done in 3 hours (that he works together with Sal)=100%60%=40% (C)




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