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Robin split a total of $24,000 between 2 investments, X and Y. If inve
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Updated on: 20 Feb 2017, 01:39
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Robin split a total of $24,000 between 2 investments, X and Y. If investment Y earns 7% simple annual interest, how much of that total did Robin put into investment Y? (1) Each investment earns the same dollar amount of the interest annually. (2) Investment X earns 5 percent simple annual interest.
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Originally posted by RyanDe680 on 09 May 2008, 17:14.
Last edited by Bunuel on 20 Feb 2017, 01:39, edited 2 times in total.
Renamed the topic, edited the question, added the OA and moved to DS forum.



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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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09 May 2008, 17:59
1. 24000x=y y*1.07=x*interest rate (24000x)*.07=x*interest rate two variables insufficient
2. I don't know the total amount earned in interest annually insufficient
1&2) (24000x)*.07=x*.05 > x is some numeric value
24000x=y > y is some numeric value
C



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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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11 May 2008, 14:41
OA is C.
My confusion is how do you know what the "investment" is? Any investment can earn a certain percentage, but it doesn't mean you can calculate based off of that how much you invested in it....
Am I thinking too far into this?



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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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11 May 2008, 16:19
RyanDe680 wrote: OA is C.
My confusion is how do you know what the "investment" is? Any investment can earn a certain percentage, but it doesn't mean you can calculate based off of that how much you invested in it....
Am I thinking too far into this? wrong. notice the 24000x it is key to solving the problem.



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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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05 Jan 2016, 21:45
Bunuel or some moderator, please change "If investment earns 7% simple annual interest" to "If investment Y earns 7% simple annual interest" or merge it with this topic: http://gmatclub.com/forum/robinsplitatotalof24000between2investmentsx37523.html. Thanks!



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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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05 Jan 2016, 22:06
TooLong150 wrote: Bunuel or some moderator, please change "If investment earns 7% simple annual interest" to "If investment Y earns 7% simple annual interest" or merge it with this topic: http://gmatclub.com/forum/robinsplitatotalof24000between2investmentsx37523.html. Thanks! Hi, you are right that the Q seems to replicate the one you have linked... But this Q also can act as a valid Q the way it is and would have C as the answer
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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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12 Jun 2016, 02:40
RyanDe680 wrote: Robin split a total of $24,000 between 2 investments, X and Y. If investment earns 7% simple annual interest, how much of that total did Robin put into investment Y?
(1) Each investment earns the same dollar amount of the interest annually. (2) Investment X earns 5 percent simple annual interest. considering both statements together. total interest earned 7% of 24000=1680 as per statement(1) each investment earns 1680/2=840 as nterest from (2) investment X earns 5 percent simple annual interest if a part of investment is X then another invested amount=24000X so X*5/100*1=840 giving x=12800 and Y=2400012800=11200 Ans C



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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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10 Feb 2017, 23:31
1 is insufficient because we do not know any relationship between the interest rates or the sums of money. 2 is insufficient because you can't tell anything about investment y, since, again, you do not have a relationship between x and y. Put together, the two stmts are more efficient in solving the mystery. Since we know that 0.07y = 0.05x or that 7y = 5x and we also know that x + y = 24000. This is a simple set of equations with two unknown numbers, x and y. So 7y = 5x x + y = 24 000 Solve this system and you'll get the answer. So answer is C.
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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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11 Feb 2017, 01:16
anairamitch1804 wrote: 1 is insufficient because we do not know any relationship between the interest rates or the sums of money. 2 is insufficient because you can't tell anything about investment y, since, again, you do not have a relationship between x and y.
Put together, the two stmts are more efficient in solving the mystery. Since we know that 0.07y = 0.05x or that 7y = 5x and we also know that x + y = 24000. This is a simple set of equations with two unknown numbers, x and y. So 7y = 5x x + y = 24 000 Solve this system and you'll get the answer.
So answer is C. Hi, Please refer the highlighted part. It is not correct. 7 % interest rate is on the total amount, i.e. on 24000, not on y. Thanks.



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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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20 Feb 2017, 01:14
RyanDe680 wrote: Robin split a total of $24,000 between 2 investments, X and Y. If investment earns 7% simple annual interest, how much of that total did Robin put into investment Y?
(1) Each investment earns the same dollar amount of the interest annually. (2) Investment X earns 5 percent simple annual interest. Question stem is not very much clear, because 7% rate for Y is not explicitly mentioned . M i ryt?



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Robin split a total of $24,000 between 2 investments, X and Y. If inve
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20 Feb 2017, 01:40
gauraha wrote: RyanDe680 wrote: Robin split a total of $24,000 between 2 investments, X and Y. If investment earns 7% simple annual interest, how much of that total did Robin put into investment Y?
(1) Each investment earns the same dollar amount of the interest annually. (2) Investment X earns 5 percent simple annual interest. Question stem is not very much clear, because 7% rate for Y is not explicitly mentioned . M i ryt? Edited. The stem reads: Robin split a total of $24,000 between 2 investments, X and Y. If investment Y earns 7% simple annual interest, how much of that total did Robin put into investment Y?
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Robin split a total of $24,000 between 2 investments, X and Y. If inve
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14 Dec 2017, 01:29
Stem Gives us
X + Y = 24000
Statement 1 Alone is insufficient. As 7 % of small amount can equal to 5 % of bigger amount . Or vice versa. Statement 2 in clearly insufficient.
Combining two.
[7/100] * y= [5/100] *x Equation 1
Stem gave us X + Y =24000 > X=24000 Y Equation 2
Two variables & Two equations. Hence C is the answer.



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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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24 Sep 2018, 15:08
RyanDe680 wrote: Robin split a total of $24,000 between 2 investments, X and Y. If investment Y earns 7% simple annual interest, how much of that total did Robin put into investment Y?
(1) Each investment earns the same dollar amount of the interest annually. (2) Investment X earns 5 percent simple annual interest.
\(\left. \matrix{ X:\,\,\,24 \cdot k\,\,\,\,\,\,\,;\,\,\,\,\,\,{i \over {100}}\left( {24k} \right)\,\,\,\,\,{\rm{annual}}\,\,{\rm{simple}}\,\,{\rm{interest}}\,\,\left( * \right) \hfill \cr Y:\,\,\,24 \cdot \left( {1  k} \right)\,\,\,\,\,;\,\,\,\,\,\,{7 \over {100}}\left[ {24\left( {1  k} \right)} \right]\,\,\,\,{\rm{annual}}\,\,{\rm{simple}}\,\,{\rm{interest}}\,\,\, \hfill \cr} \right\}\,\,\,\,\,\,\,\,\left[ {{\rm{unit}}:\,\,\,\$ \,\,{{10}^3}} \right]\) \(\left( * \right)\,\,{\rm{just}}\,\,{\rm{a}}\,\,{\rm{initial}}\,\,{\rm{assumption}}\,\) \(? = 24\left( {1  k} \right)\,\,\,\,\,\,\,\, \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,\boxed{? = k}\,\,\,\,\,\,\left( {0 < k < 1} \right)\,\) \(\left( 1 \right)\,\,\,\frac{i}{{100}}\left( {24k} \right) = \frac{7}{{100}}\left[ {24\left( {1  k} \right)} \right]\,\,\,\,\,\, \Rightarrow \,\,\,\,\,ik = 7\left( {1  k} \right)\,\,\,\,\,\left( {**} \right)\) \(\left\{ \matrix{ \,{\rm{Take}}\,\,i = 7\,\,\,\mathop \Rightarrow \limits^{\left( {**} \right)} \,\,\,? = k = 0.5\,\,\,\, \hfill \cr \,{\rm{Take}}\,\,i = 0.0001\,\,\,\left( { \cong 0} \right)\,\,\,\mathop \Rightarrow \limits^{\left( {**} \right)} \,\,\,? = k \cong 1\,\,\,\, \hfill \cr} \right.\) \(\left( 2 \right)\,\,i = 5\,\,\,\left( {{\rm{trivial}}\,\,{\rm{bifurcation}}} \right)\,\,\,\left\{ \matrix{ \,{\rm{Take}}\,\,k = 0.5\,\,\,\, \hfill \cr \,{\rm{Take}}\,\,k = 0.6\,\,\,\, \hfill \cr} \right.\,\,\) \(\left( {1 + 2} \right)\,\,\,\left\{ \matrix{ \,\,\left( {**} \right)\,\,\,ik = 7\left( {1  k} \right)\,\,\,\, \hfill \cr \,\,\,i = 5 \hfill \cr} \right.\,\,\, \Rightarrow \,\,\,\,k\,\,{\rm{unique}}\,\,\, \Rightarrow \,\,\,\,{\rm{SUFF}}.\,\,\,\,\,\) This solution follows the notations and rationale taught in the GMATH method. Regards, Fabio.
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Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve
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25 Sep 2018, 03:18
RyanDe680 wrote: Robin split a total of $24,000 between 2 investments, X and Y. If investment Y earns 7% simple annual interest, how much of that total did Robin put into investment Y?
(1) Each investment earns the same dollar amount of the interest annually. (2) Investment X earns 5 percent simple annual interest. Statement 1:Test one case that also satisfies Statement 2. Case 1: X = 5% and Y = 7% For 5% interest and 7% percent interest to yield the same dollar amount, $7 must be invested at 5% interest for every $5 invested at 7% interest: X > $7(0.05) = $0.35. Y > $5(0.07) = $0.35. Thus: \(\frac{X}{Y} = \frac{$7}{$5}\), implying that \(\frac{5}{12}\) of the $24,000 must be invested in Y: \(\frac{5}{12} * 24,000 = 10,000\) Test one case that does NOT also satisfy Statement 2. Case 2: X = 3% and Y = 7% For 3% interest and 7% percent interest to yield the same dollar amount, $7 must be invested at 3% interest for every $3 invested at 7% interest: X > $7(0.03) = $0.21. Y > $3(0.07) = $0.21. Thus: \(\frac{X}{Y} = \frac{$7}{$3}\), implying that \(\frac{3}{10}\) of the $24,000 must be invested in Y: \(\frac{3}{10}* 24,000 = 7200\) Since the amount invested in Y can be different values, INSUFFICIENT. Statement 2:Here, the amount invested in Y can be any monetary value between $0 and $24,000. INSUFFICIENT. Statements combined:Only Case 1 satisfies both statements. In Case 1, the amount invested in Y = 10,000. SUFFICIENT.
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