• 7 CATs FREE!
    If you earn 100 Forum Points

    Engage in the Beat The GMAT forums to earn
    100 points for $49 worth of Veritas practice GMATs FREE

    Veritas Prep
    VERITAS PRACTICE GMAT EXAMS
    Earn 10 Points Per Post
    Earn 10 Points Per Thanks
    Earn 10 Points Per Upvote
    REDEEM NOW

Julie opened a lemonade stand and sold lemonade in two

This topic has 4 expert replies and 0 member replies

Julie opened a lemonade stand and sold lemonade in two

Post

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Difficult



Julie opened a lemonade stand and sold lemonade in two different sizes, a 52-cent (12oz) and a 58-cent (16oz) size. How many 52-cent (12oz) lemonade drinks did Julie sell?

(1) Julie sold a total of 9 lemonades
(2) The total value of the lemonade drinks Julie sold was $4.92

OA B

Source: Veritas Prep

  • +1 Upvote Post
  • Quote
  • Flag
Post
BTGmoderatorDC wrote:
Julie opened a lemonade stand and sold lemonade in two different sizes, a 52-cent (12oz) and a 58-cent (16oz) size. How many 52-cent (12oz) lemonade drinks did Julie sell?

(1) Julie sold a total of 9 lemonades
(2) The total value of the lemonade drinks Julie sold was $4.92
Source: Veritas Prep
$$\left\{ \matrix{
\,m \ge 1\,\,{\mathop{\rm int}} \,\,\,12{\rm{oz - units}}\,\,,\,\,52\,{\rm{cents}}\,{\rm{each}} \hfill \cr
\,n \ge 1\,\,{\mathop{\rm int}} \,\,\,\,16{\rm{oz - units}}\,\,,\,\,58\,{\rm{cents}}\,{\rm{each}}\,\,\, \hfill \cr} \right.\,\,\,\,\left( * \right)$$
$$? = m$$
$$\left( 1 \right)\,\,m + n = 9\,\,\,\left\{ \matrix{
\,{\rm{Take}}\,\,\left( {m,n} \right) = \left( {1,8} \right)\,\,\,\, \Rightarrow \,\,\,? = 1\,\, \hfill \cr
\,{\rm{Take}}\,\,\left( {m,n} \right) = \left( {2,7} \right)\,\,\,\, \Rightarrow \,\,\,? = 2\,\, \hfill \cr} \right.$$

Money unit will be CENTS. (All amounts in cents are integers!)
$$\left( 2 \right)\,\,52m + 58n = 492\,\,\,\,\,\,\mathop \Rightarrow \limits^{:\,\,2} \,\,\,\,\,26m + 29n = 246\,\,\,$$
$$\left[ {29n\,\,\mathop = \limits^{\left( * \right)} \,} \right]\,\,{\rm{positive}}\,\,{\rm{multiple}}\,\,{\rm{of}}\,\,29\,\, = \,\,\,246 - 26m = 2\left( {123 - 13m} \right)\,\,\,\,\,\mathop \Rightarrow \limits^{{\rm{GCF}}\,\left( {2,29} \right)\,\, = \,\,1} \,\,\,123 - 13m\,\,{\rm{is}}\,\,{\rm{a}}\,\,{\rm{positive}}\,\,{\rm{multiple}}\,\,{\rm{of}}\,\,29$$
\[\left. \begin{gathered}
m = 1\,\,\,\, \Rightarrow \,\,\,123 - 13 = 110\,\,\,\,\left( {{\text{NO}}} \right) \hfill \\
m = 2\,\,\,\, \Rightarrow \,\,\,123 - 26 = 97\,\,\left[ { = 110 - 13} \right]\,\,\,\,\,\left( {{\text{NO}}} \right) \hfill \\
m = 3\,\,\,\, \Rightarrow \,\,\,123 - 39 = 84\,\,\left[ { = 97 - 13} \right]\,\,\,\,\,\,\left( {{\text{NO}}} \right)\,\,\,\, \hfill \\
m = 4\,\,\,\, \Rightarrow \,\,\,84 - 13 = 71\,\,\,\,\,\,\left( {{\text{NO}}} \right) \hfill \\
\boxed{m = 5}\,\,\,\, \Rightarrow \,\,\,71 - 13 = 58 = 2 \cdot 29\,\,\,\,\,\left( {{\text{YES}}} \right)\,\,\,\,\,\,\,\,\,\,\, \hfill \\
m = 6\,\,\,\, \Rightarrow \,\,\,58 - 13 = 45\,\,\,\,\,\left( {{\text{NO}}} \right) \hfill \\
m = 7\,\,\,\, \Rightarrow \,\,\,45 - 13 = 32\,\,\,\,\,\left( {{\text{NO}}} \right) \hfill \\
m = 8\,\,\,\, \Rightarrow \,\,\,32 - 13 = 19\,\,\,\,\,\left( {{\text{NO}}} \right) \hfill \\
\end{gathered} \right\}\,\,\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,\,? = 5\]

This solution follows the notations and rationale taught in the GMATH method.

Regards,
Fabio.

_________________
Fabio Skilnik :: https://GMATH.net (Math for the GMAT)
Testimonials :: https://GMATH.net/testimonials.html
Course release PROMO : finish our test drive till 31/Oct with (at least) 60 correct answers out of 92 (12-questions Mock included) to gain a 60% discount!

  • +1 Upvote Post
  • Quote
  • Flag
Post
BTGmoderatorDC wrote:
Julie opened a lemonade stand and sold lemonade in two different sizes, a 52-cent (12oz) and a 58-cent (16oz) size. How many 52-cent (12oz) lemonade drinks did Julie sell?

(1) Julie sold a total of 9 lemonades
(2) The total value of the lemonade drinks Julie sold was $4.92

OA B

Source: Veritas Prep
Given: Julie sells lemonade in two different sizes, a 52-cent (12oz) and a 58-cent (16oz) size

Question: How many 52-cent (12oz) lemonade drinks did Julie sell?

Let's take each statement one by one.

(1) Julie sold a total of 9 lemonades.

Certainly insufficient.

(2) The total value of the lemonade drinks Julie sold was $4.92.

Say, the number of 12oz lemonades sold is x and the number of 16oz lemonades sold is y.

Then, 52x + 58y = 492

=> 26x + 29y = 246

x = (246 - 29y)/26

= 9 + (12 - 29y)/26

= 9 + (12 - 26y - 3y)/26

= 9 + (12 - 3y)/26 - 26y/26

= 9 + (12 - 3y)/26 - y

Since x is a positive integer, (12 - 3y) must be a multiple of 26.

Let's try some values for y to make (12 - 3y) must be a multiple of 26.

@y = 4, we have (12 - 3y) => 12 - 3*4 = 12 - 12 = 0 -- a multiple of 26.

Thus, x = 9 + 0 - 4 = 5.

We must try a few more values for y so that (12 - 3y) must be a multiple of 26 and x is a positive integer.

Note that at higher values of y, the term [(12 - 3y)/26 - y] would be negative, making x a negative integer, which is an invalid value. You'll find that there is no another possible valid value of y. Thus, y = 4 and y = 5. Sufficient.

The correct answer: B

Hope this helps!

-Jay
_________________
Manhattan Review GMAT Prep

Locations: New York | Bangalore | Guangzhou | Buenos Aires | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post
BTGmoderatorDC wrote:
Julie opened a lemonade stand and sold lemonade in two different sizes, a 52-cent (12oz) and a 58-cent (16oz) size. How many 52-cent (12oz) lemonade drinks did Julie sell?

(1) Julie sold a total of 9 lemonades
(2) The total value of the lemonade drinks Julie sold was $4.92

Let X = the number of 52¢ lemonades and Y = the number of 58¢ lemonades.
Since the question stem asks for the number of 52¢ lemonades, we get:
What is the value of X?

Statement 1:
X+Y = 9
Since X can be any value between 0 and 9, inclusive, INSUFFICIENT.

Statement 2:
52X + 58Y = 492

Since the two statements cannot contradict each other, an integral solution for the equation above must be yielded when X+Y=9.
If a total of 9 lemonades are sold, the equation above implies the following:
Average cost per lemonade = 492/9 ≈ 54.66.
Since the average cost is just a bit closer to 52 than to 58, the number of 52¢ lemonades must be a just bit greater than the number of 58¢ lemonades, implying that X=5 and Y=4:
5*52 + 4*58 = 260 + 232 = 492.

In the case above, X:Y = 5:4.
Check whether OTHER revenue ratios are also possible.
Since the lemonade values are 52¢ and 58¢, the revenue ratio can be altered only by adding a multiple of 52 and 58 to X or Y, while subtracting this multiple from the other variable.
Since 52 = 2*26 and 58 = 2*29, the LCM of 52 and 58 = 2*26*29.
If 2*26*29 is added to either 52¢ or 58¢, the sum will exceed 492¢.
Thus, the revenue ratio CANNOT be altered, implying that only ONE revenue ratio will satisfy statement 2:
X=5 and Y=4.
Thus, X=5.
SUFFICIENT.

The correct answer is B.

_________________
Mitch Hunt
Private Tutor for the GMAT and GRE
GMATGuruNY@gmail.com

If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon.

Available for tutoring in NYC and long-distance.
For more information, please email me at GMATGuruNY@gmail.com.
Student Review #1
Student Review #2
Student Review #3

  • +1 Upvote Post
  • Quote
  • Flag
Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.

GMAT/MBA Expert

Post
This question illustrates a common trap on the GMAT.

For statement 2, we're able to write the equation 52x + 58y = 492 , and in high school we learned that, if we're given 1 equation with 2 variables, we cannot find the value of either variable. However, if we restrict the variables to positive integers within a certain range of values, then there are times when we can find the value of a variable if we're given 1 equation with 2 variables.

Here's another question that exploits this common misconception: https://www.beatthegmat.com/stamps-t288085.html

Cheers,
Brent

_________________
Brent Hanneson – Creator of GMATPrepNow.com
Use our video course along with Beat The GMAT's free 60-Day Study Guide

Sign up for our free Question of the Day emails
And check out all of our free resources

  • +1 Upvote Post
  • Quote
  • Flag
GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
  • Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors
  • The Princeton Review
    FREE GMAT Exam
    Know how you'd score today for $0

    Available with Beat the GMAT members only code

    MORE DETAILS
    The Princeton Review
  • Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh

Top First Responders*

1 fskilnik@GMATH 74 first replies
2 Jay@ManhattanReview 49 first replies
3 Brent@GMATPrepNow 47 first replies
4 GMATGuruNY 43 first replies
5 Rich.C@EMPOWERgma... 36 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

Most Active Experts

1 image description fskilnik@GMATH

GMATH Teacher

195 posts
2 image description Scott@TargetTestPrep

Target Test Prep

183 posts
3 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

123 posts
4 image description Max@Math Revolution

Math Revolution

89 posts
5 image description GMATGuruNY

The Princeton Review Teacher

87 posts
See More Top Beat The GMAT Experts