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The ratio of R to S is 3 to 5, what is the value of the rati
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Updated on: 12 Aug 2014, 01:33
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The ratio of R to S is 3 to 5, what is the value of the ratio (R + K)/(S + K)? (1) R = 12 (2) K = 7
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Originally posted by NoHalfMeasures on 12 Aug 2014, 01:30.
Last edited by Bunuel on 12 Aug 2014, 01:33, edited 1 time in total.
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Re: The ratio of R to S is 3 to 5, what is the value of the rati
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12 Aug 2014, 01:39



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The ratio of R to S is 3 to 5, what is the value of the rati
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29 Oct 2014, 21:05
Hi Bunuel, Just a silly basic question... Given that ratio of R to S is 3 to 5, We cannot compute this as 3+7 / 5+7 Correct? Hence "B" would be wrong. Pls clarify my doubt as in why we cannot compute this as 3+7 / 5+7. Thanks Bunuel wrote: The ratio of R to S is 3 to 5, what is the value of the ratio (R + K)/(S + K)?
R:S = 3:5.
(1) R = 12 > S = 20. We need K. Not sufficient.
(2) K = 7 > (R + K)/(S + K) = (R + 7)/(5R/3 + 7). The ratio will change depending on R. Not sufficient.
(1)+(2) We know the values of all variables, thus we can get the desired ratio. Sufficient.
Answer: C.



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Re: The ratio of R to S is 3 to 5, what is the value of the rati
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30 Oct 2014, 01:46
Buddyisrael wrote: Hi Bunuel, Just a silly basic question... Given that ratio of R to S is 3 to 5, We cannot compute this as 3+7 / 5+7 Correct? Hence "B" would be wrong. Pls clarify my doubt as in why we cannot compute this as 3+7 / 5+7. Thanks Bunuel wrote: The ratio of R to S is 3 to 5, what is the value of the ratio (R + K)/(S + K)?
R:S = 3:5.
(1) R = 12 > S = 20. We need K. Not sufficient.
(2) K = 7 > (R + K)/(S + K) = (R + 7)/(5R/3 + 7). The ratio will change depending on R. Not sufficient.
(1)+(2) We know the values of all variables, thus we can get the desired ratio. Sufficient.
Answer: C. Yes, you are right we cannot do that way. The ratio of R to S is 3 to 5, does not mean that R is 3 and S is 5, they can be (6, 10), (9, 15), (12, 20)...
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Re: The ratio of R to S is 3 to 5, what is the value of the rati
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02 Dec 2014, 19:04
1. R = 12 that gives us S but we do not know K. NS 2. K = 7 but we do not know what is S, S can be 5, 10 15 so no.. NS 1&2. we get R, S and K Sufficient. Answer: C MensaNumber wrote: The ratio of R to S is 3 to 5, what is the value of the ratio (R + K)/(S + K)?
(1) R = 12 (2) K = 7
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The ratio of R to S is 3 to 5, what is the value of the rati
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20 Apr 2015, 08:08
Folks,
Since R:S::3:5, why can't we use R=3K and S=5K then we don't need information from 1. and 2. Then shouldn't D. be the answer?
Thanks



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Re: The ratio of R to S is 3 to 5, what is the value of the rati
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20 Apr 2015, 09:11
Reaper wrote: Folks,
Since R:S::3:5, why can't we use R=3K and S=5K then we don't need information from 1. and 2. Then shouldn't D. be the answer?
Thanks Hi Reaper  if R & S are in a ratio of 3:5, we can surely write them as 3x and 5x respectively. However, in this case we do not know whether x = K. Hence your interpretation of answer being D will not hold. Let me also explain this with an example. Assume R = 12 and S = 20, then R & S are in the ratio of 3:5. So, R & S can be written as 3x and 5x respectively for x =4. Depending upon the values of R & S, the value of x would vary. For R = 15 & S = 25, value of x would be 5 and so on. Since we do not know the value of K, we can't say for sure if R=3K and S=5k respectively. Hope this helps! Regards Harsh
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Re: The ratio of R to S is 3 to 5, what is the value of the rati
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20 Apr 2015, 17:06
Hi All, This DS question can be dealt with in a couple of different ways. You can use "math theory" on this prompt, but unless your understanding of the concepts is PERFECT, you might make a little mistake and select an incorrect answer (and not even know it). By TESTing VALUES, you can PROVE the correct answer (and do so with a certain amount of ease). We're told that the ratio of R to S is 3 to 5. We're asked for the value of (R + K)/(S + K). Fact 1: R = 12 With the given ratio (R:S = 3:5), we now know that S = 20. We don't know the value of K though... IF.... K = 0 The answer to the question is (12+0)/(20+0) = 12/20 = 3/5 IF... K = 1 The answer to the question is (12+1)/(20+1) = 13/21 Fact 1 is INSUFFICIENT Fact 2: K = 7 We don't know the values of R and S, but we DO know that they fall into the ratio of 3:5...... IF... R = 3 S = 5 The answer to the question is (3+7)/(5+7) = 10/12 = 5/6 IF... R = 6 S = 10 The answer to the question is (6+7)/(10+7) = 13/17 Fact 2 is INSUFFICIENT Combined, we know.... R = 12 (so S = 20) K = 7 The answer to the question MUST be (12+7)/(20+7) = 19/27 Combined, SUFFICIENT Final Answer: GMAT assassins aren't born, they're made, Rich
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Re: The ratio of R to S is 3 to 5, what is the value of the rati
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20 Apr 2015, 18:26
Hi All, This is a tricky question. Here students may do careless error by chosing D or B. But the answer is together sufficient: Ratio of R to S is 3 to 5. Then value of R to S is 3x to 5x. Now the question asks for value of the ratio R+k to S+k. So that’s 3x+k to 5x+k. We need x and k values. Statement 1 : Not sufficient: From statement 2 we only get x value because R= 3x and 3x=12 so x = 4. But no info about K. So not sufficient. Statement 2 : Not sufficient: Gives the K value and no info about x. So not sufficient. Together it is sufficient. Because we get both x and K values. So answer is C.
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Re: The ratio of R to S is 3 to 5, what is the value of the rati
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20 Apr 2015, 19:57
Yes Harsh, it makes sense. x=K is not definitive.
Thanks



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Re: The ratio of R to S is 3 to 5, what is the value of the rati
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