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Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 00:58
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Containers A and B each contain 8 gold coins, 12 silver coins, and nothing else. Container C contains 1 gold coin, 4 silver coins, and nothing else. A container is chosen at random and then a coin is chosen at random from that container. What is the probability that the chosen coin is silver? A. 4/15 B. 2/5 C. 7/15 D. 3/5 E. 2/3
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Last edited by chetan2u on 29 Jul 2017, 05:22, edited 2 times in total.
updated the OA



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Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 01:02
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Is this approach correct?
(1/3 x 0/8) + (1/3 x 12/20) + (1/3 x 4/5) = 7/15
i.e. Prob of selecting that box X Probability of getting a silver in that box
summation of this for all 3 boxes



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Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 01:15
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Does anyone think the question is quite misleading? Containers A and B "each" contains 8 gold coins, 12 silver coins, and nothing else. Does this not indicate that A contains 8G and 12S and that B contains the same coins as A? Only after I finish my calculation that I realized this way was wrong.



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Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 01:38
3newton wrote: Is this approach correct?
(1/3 x 0/8) + (1/3 x 12/20) + (1/3 x 4/5) = 7/15
i.e. Prob of selecting that box X Probability of getting a silver in that box
summation of this for all 3 boxes Hey 3newton, Can you please tell why you have multiplied 0/3. Rest of he things are clear. Tanks in advance. Sent from my Lenovo TAB S850LC using GMAT Club Forum mobile app



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Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 01:39
Rather I would have gone for 1/3(12/20+12/20+4/5). Thus would have led to 2/3. Ans E. Please correct my understanding of needed. Sent from my Lenovo TAB S850LC using GMAT Club Forum mobile app



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Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 05:06
kumarparitosh123 wrote: Rather I would have gone for 1/3(12/20+12/20+4/5). Thus would have led to 2/3. Ans E. Please correct my understanding of needed. Sent from my Lenovo TAB S850LC using GMAT Club Forum mobile appThe line "Containers A and B each contain 8 gold coins, 12 silver coins, and nothing else" is quite misleading here. What it actually wants to say is that Container A contains 8 Gold coins and nothing else, and Container B contains 12 Silver coins and nothing else. Seems to be a poor quality question..



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Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 05:21
3newton wrote: Containers A and B each contain 8 gold coins, 12 silver coins, and nothing else. Container C contains 1 gold coin, 4 silver coins, and nothing else. A container is chosen at random and then a coin is chosen at random from that container. What is the probability that the chosen coin is silver?
A. 4/15
B. 2/5
C. 7/15
D. 3/5
E. 2/3 Hi... the way Q is written, answer is clearly E..... Q means BOTH A and B contain 8G and 12S. container C contains 1G and 4S..Now how have you interpreted it as 0 silver in A is wrong...Any of three can be choosen, so choosing each means probability of 1/3.. total \(\frac{1}{3}*\frac{12}{20}*2+\frac{1}{3}*\frac{4}{5} = \frac{2}{3}\) E
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Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 05:22
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3newton wrote Quote: Containers A and B each contain 8 gold coins, 12 silver coins, and nothing else. Container C contains 1 gold coin, 4 silver coins, and nothing else. A container is chosen at random and then a coin is chosen at random from that container. What is the probability that the chosen coin is silver?
A. 4/15
B. 2/5
C. 7/15
D. 3/5
E. 2/3 K_Leon wrote: Does anyone think the question is quite misleading? Containers A and B "each" contains 8 gold coins, 12 silver coins, and nothing else. Does this not indicate that A contains 8G and 12S and that B contains the same coins as A? Only after I finish my calculation that I realized this way was wrong. Yes. I remain confused. I got the correct answer through no fault of my own. I guessed. A thorough discussion of "each" and "both" belongs in SC, so I'll keep it as short as I can. One hat I wear is editor of English prose. "Each" refers to every one of any number, when considered individually or separately. "Both" refers to two, taken together. "Each," almost always, is a singular subject (hence singular verb). "Both" is a plural subject. The prompt's plural verb "contain" implies both. ???? "Each" should be used to emphasize the individuality of separate conditions. "The company gave both women $100,000." Unclear. Corrected: "The company gave each woman $100,000." (The women did not split the $100,000.) Clarity would be simple to achieve. "Jars A and B both contain ..." Or "Jars A and B contain, respectively, 8 gold and 12 silver coins." I still can't figure out how, in 3newton 's response, A has 0 silver coins of 8 total but B has 12 silver coins of 20 total. Doesn't A also have 20 coins? If A = 8 total and B = 12 total, I think the equation is (1/3 * 0/8) + (1/3 * 12/12) + (1/3 * 4/5) = 3/5 kumarparitosh123 , I think you are correct. If A and B both have 8 gold and 12 silver coins, I agree that the equation is (1/3 * 12/20) + (1/3 * 12/20) + (1/3 * 4/5) = 2/3 That said, if words were clear and OA were different, the content would be interesting. 3newton , are you sure the OA is correct? chetan2u , I disagree respectfully. I don't think there's anything clear about it. Both answers D and E are defensible.
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Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 05:33
genxer123 wrote: 3newton wrote Quote: Containers A and B each contain 8 gold coins, 12 silver coins, and nothing else. Container C contains 1 gold coin, 4 silver coins, and nothing else. A container is chosen at random and then a coin is chosen at random from that container. What is the probability that the chosen coin is silver?
A. 4/15
B. 2/5
C. 7/15
D. 3/5
E. 2/3 K_Leon wrote: Does anyone think the question is quite misleading? Containers A and B "each" contains 8 gold coins, 12 silver coins, and nothing else. Does this not indicate that A contains 8G and 12S and that B contains the same coins as A? Only after I finish my calculation that I realized this way was wrong. Yes. I remain confused. I got the correct answer through no fault of my own. I guessed. A thorough discussion of "each" and "both" belongs in SC, so I'll keep it as short as I can. One hat I wear is editor of English prose. "Each" refers to every one of any number, when considered individually or separately. "Both" refers to two, taken together. "Each," almost always, is a singular subject (hence singular verb). "Both" is a plural subject. The prompt's plural verb "contain" implies both. ???? "Each" should be used to emphasize the individuality of separate conditions. "The company gave both women $100,000." Unclear. Corrected: "The company gave each woman $100,000." (The women did not split the $100,000.) Clarity would be simple to achieve. "Jars A and B both contain ..." Or "Jars A and B contain, respectively, 8 gold and 12 silver coins." I still can't figure out how, in 3newton 's response, A has 0 silver coins of 8 total but B has 12 silver coins of 20 total. Doesn't A also have 20 coins? If A = 8 total and B = 12 total, I think the equation is (1/3 * 0/8) + (1/3 * 12/12) + (1/3 * 4/5) = 3/5 kumarparitosh123 , I think you are correct. If A and B both have 8 gold and 12 silver coins, I agree that the equation is (1/3 * 12/20) + (1/3 * 12/20) + (1/3 * 4/5) = 2/3 That said, if words were clear and OA were different, the content would be interesting. 3newton , are you sure the OA is correct? chetan2u , I disagree respectfully. I don't think there's anything clear about it. Both answers D and E are defensible. Hi, Disagreement is always good, and with respect is even better . So I may agree with what you have written but not with D as answer in any way, neither mathematically or grammatically..an error of contain/contains is perfectly fine in the forum, may not be in actuals. but there too it would mean the same.say if I take what you say  Quote: Containers A and B each contain 8 gold coins, 12 silver coins, and nothing else. could mean the equation is (1/3 * 0/8) + (1/3 * 12/12) + (1/3 * 4/5) = 3/5 so A has 8 gold coins , B has 12 silver BUT WHO has " nothing else"so this solution does not stand grammatically too.. E is the only possible answer.
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Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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29 Jul 2017, 07:21
chetan2u wrote: genxer123 wrote: chetan2u , I disagree respectfully. I don't think there's anything clear about it. Both answers D and E are defensible. Hi, Disagreement is always good, and with respect is even better . So I may agree with what you have written but not with D as answer in any way, neither mathematically or grammatically..an error of contain/contains is perfectly fine in the forum, may not be in actuals. but there too it would mean the same.say if I take what you say  Quote: Containers A and B each contain 8 gold coins, 12 silver coins, and nothing else. could mean the equation is (1/3 * 0/8) + (1/3 * 12/12) + (1/3 * 4/5) = 3/5 so A has 8 gold coins , B has 12 silver BUT WHO has " nothing else"so this solution does not stand grammatically too.. E is the only possible answer. "A has 8 gold coins, B has 12 silver coins, and [in each there is] nothing else." That's correct, grammatically.
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Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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28 Aug 2017, 23:20
I did a more 'one at a time' probability and added them up: > prob of container: 1/3 (choosing one out of 3 containers A,B,C) > prob of silver per container > if either A and B > then 1/12 > if either C > then 1/4 Prob of all silver > 1/4 + 1/16 = 1/3 > Prob of silver and container =1/3 + 1/3 >2/3 (E)



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Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not [#permalink]
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28 Aug 2017, 23:24
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Also, I do notice an error in phrasing 'each contain'  since I read container A and B; it skipped my attention. (this is not advisable anyway in GMAT exam where every word is important) . Now it would complicate matters because it means A and B total would be 16 gold and 24 silver coins > I think this question needs to be rephrased




Re: Containers A and B each contain 8 gold coins, 12 silver coins, and not
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