GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 19 Feb 2019, 10:09

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

## Events & Promotions

###### Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT Prep Hour

February 20, 2019

February 20, 2019

08:00 PM EST

09:00 PM EST

Strategies and techniques for approaching featured GMAT topics. Wednesday, February 20th at 8 PM EST

February 21, 2019

February 21, 2019

10:00 PM PST

11:00 PM PST

Kick off your 2019 GMAT prep with a free 7-day boot camp that includes free online lessons, webinars, and a full GMAT course access. Limited for the first 99 registrants! Feb. 21st until the 27th.

### Show Tags

Updated on: 20 Feb 2017, 01:39
2
9
00:00

Difficulty:

25% (medium)

Question Stats:

76% (01:43) correct 24% (01:41) wrong based on 377 sessions

### HideShow timer Statistics

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. 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. Manager Joined: 16 Sep 2007 Posts: 208 Re: Robin split a total of$24,000 between 2 investments, X and Y. If inve  [#permalink]

### Show Tags

09 May 2008, 17:59
1.
24000-x=y
y*1.07=x*interest rate
(24000-x)*.07=x*interest rate
two variables
insufficient

2.
I don't know the total amount earned in interest annually
insufficient

1&2)
(24000-x)*.07=x*.05
->
x is some numeric value

24000-x=y
->
y is some numeric value

C
Manager
Joined: 27 Jun 2007
Posts: 182

### Show Tags

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 24000-x it is key to solving the problem.
Manager
Joined: 10 Mar 2013
Posts: 192
GMAT 1: 620 Q44 V31
GMAT 2: 690 Q47 V37
GMAT 3: 610 Q47 V28
GMAT 4: 700 Q50 V34
GMAT 5: 700 Q49 V36
GMAT 6: 690 Q48 V35
GMAT 7: 750 Q49 V42
GMAT 8: 730 Q50 V39

### Show Tags

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/robin-split-a-total-of-24-000-between-2-investments-x-37523.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
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html
4) Base while finding % increase and % decrease : https://gmatclub.com/forum/percentage-increase-decrease-what-should-be-the-denominator-287528.html

GMAT Expert

VP
Joined: 05 Mar 2015
Posts: 1001
Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve [#permalink] ### Show Tags 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=24000-X
so X*5/100*1=840
giving x=12800
and Y=24000-12800=11200
Ans C
Director
Joined: 26 Oct 2016
Posts: 636
Location: United States
Schools: HBS '19
GMAT 1: 770 Q51 V44
GPA: 4
WE: Education (Education)

### Show Tags

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.

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.
Intern
Joined: 01 Jun 2013
Posts: 10
Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve [#permalink] ### Show Tags 20 Feb 2017, 01:14 1 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?
Math Expert
Joined: 02 Sep 2009
Posts: 52971
Robin split a total of $24,000 between 2 investments, X and Y. If inve [#permalink] ### Show Tags 20 Feb 2017, 01:40 1 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? _________________ Manager Joined: 02 Jan 2017 Posts: 71 Location: Pakistan Concentration: Finance, Technology GMAT 1: 650 Q47 V34 GPA: 3.41 WE: Business Development (Accounting) Robin split a total of$24,000 between 2 investments, X and Y. If inve  [#permalink]

### Show Tags

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.
GMATH Teacher
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 744
Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve [#permalink] ### Show Tags 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.
_________________

Fabio Skilnik :: GMATH method creator (Math for the GMAT)
Our high-level "quant" preparation starts here: https://gmath.net

Senior Manager
Joined: 04 Aug 2010
Posts: 349
Schools: Dartmouth College
Re: Robin split a total of $24,000 between 2 investments, X and Y. If inve [#permalink] ### Show Tags 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.

_________________

GMAT and GRE Tutor
Over 1800 followers
GMATGuruNY@gmail.com
New York, NY
If you find one of my posts helpful, please take a moment to click on the "Kudos" icon.
Available for tutoring in NYC and long-distance.