It is currently 11 Dec 2017, 12:15

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 <

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42544

Kudos [?]: 135256 [0], given: 12679

If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < [#permalink]

Show Tags

New post 16 Oct 2017, 10:15
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

80% (00:52) correct 20% (01:45) wrong based on 84 sessions

HideShow timer Statistics

If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < y < 8, which of the following expressions will have the largest value?

A. \(x^2y\)

B. \(xy^2\)

C. 5xy

D. \(\frac{4x^2y}{3}\)

E. \(\frac{x^2}{y}\)
[Reveal] Spoiler: OA

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 135256 [0], given: 12679

Expert Post
1 KUDOS received
Math Expert
User avatar
D
Joined: 02 Aug 2009
Posts: 5336

Kudos [?]: 6088 [1], given: 121

Re: If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < [#permalink]

Show Tags

New post 16 Oct 2017, 11:25
1
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
Bunuel wrote:
If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < y < 8, which of the following expressions will have the largest value?

A. \(x^2y\)

B. \(xy^2\)

C. 5xy

D. \(\frac{4x^2y}{3}\)

E. \(\frac{x^2}{y}\)


since we have to find the largest of given expression we will have to TEST all of the choices..

A. \(x^2y\).........lets see the next

B. \(xy^2\)........y>x so \(xy^2>x^2y\)... so B till now

C. 5xy.......... in B xy is bein multiplied by something between 7 and 8 but in C it is being multiplied by 5, SO B is bigger

D. \(\frac{4x^2y}{3}\)...... y>2x so x^2y multiplied by 4/3 will still not make it bigger than xy^2

E. \(\frac{x^2}{y}\).... division is involved, so surely is the lowest

B is the winner

SECOND way
since all choices are containing x and y, it will suffice here to take LARGEST value of x and SMALLEST value of y
so x=3 and y=7..
substitue and you will get B as the answer
_________________

Absolute modulus :http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

Kudos [?]: 6088 [1], given: 121

Manager
Manager
User avatar
S
Joined: 27 Dec 2016
Posts: 194

Kudos [?]: 48 [0], given: 219

Concentration: Social Entrepreneurship, Nonprofit
GPA: 3.65
WE: Sales (Consumer Products)
Premium Member CAT Tests
Re: If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < [#permalink]

Show Tags

New post 17 Oct 2017, 03:07
Bunuel wrote:
If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < y < 8, which of the following expressions will have the largest value?

A. \(x^2y\)

B. \(xy^2\)

C. 5xy

D. \(\frac{4x^2y}{3}\)

E. \(\frac{x^2}{y}\)


I answer B.

Arrived B with plugging x=3 and y=8.
_________________

There's an app for that - Steve Jobs.

Kudos [?]: 48 [0], given: 219

Expert Post
Veritas Prep GMAT Instructor
User avatar
G
Joined: 16 Oct 2010
Posts: 7788

Kudos [?]: 18098 [0], given: 236

Location: Pune, India
Re: If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < [#permalink]

Show Tags

New post 17 Oct 2017, 04:01
Bunuel wrote:
If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < y < 8, which of the following expressions will have the largest value?

A. \(x^2y\)

B. \(xy^2\)

C. 5xy

D. \(\frac{4x^2y}{3}\)

E. \(\frac{x^2}{y}\)


To get the largest product, each variable that is multiplied should be largest and the one that divides should be smallest. The largest value x can take is slightly less than 3 and the largest value that y can take is slightly less than 8

A. \(x^2y\)

The largest value of this is about 3*3*8

B. \(xy^2\)

The largest value of this is about 3*8*8

C. 5xy

The largest value of this is about 5*3*8

D. \(\frac{4x^2y}{3}\)

The largest value of this is about 4*3*3*8/3 = 4*3*8

E. \(\frac{x^2}{y}\)

The largest value of this is about 3*3/7

A simple comparison shows that (B) is the greatest.
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Kudos [?]: 18098 [0], given: 236

VP
VP
avatar
P
Joined: 22 May 2016
Posts: 1106

Kudos [?]: 396 [0], given: 640

If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < [#permalink]

Show Tags

New post 17 Oct 2017, 04:19
Bunuel wrote:
If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < y < 8, which of the following expressions will have the largest value?

A. \(x^2y\)

B. \(xy^2\)

C. 5xy

D. \(\frac{4x^2y}{3}\)

E. \(\frac{x^2}{y}\)

You can plug in values. There are three choices:

1) mixed (improper) fractions, e.g. for x, \(\frac{5}{2}\);

2) decimals, e.g. for x, 2.5 (IMO easier than fractions); or

3) whole numbers, by far the easiest choice. This choice violates the stated conditions.

But all the operations in the answer choices involve multiplication and/or division.

In such cases, whole numbers and improper fractions greater than one all behave the same way (e.g., when squared, their value is greater).

Pick x and y values both on the high end or low end. (It might not matter, but it's safer.)

Let x = 2
Let y = 7

A. \(x^2y = (4 * 7) = 28\)

B. \(xy^2 = (2 * 49) = 98\)

C. \(5xy = (5)(14) = 70\)

D. \(\frac{4x^2y}{3} =
\frac{(4)(4)(7)}{3}\) = 37 + a little

E. \(\frac{x^2}{y} =
\frac{4}{7}\)

These answers are not close. The greatest value is

Answer B

II. Decimal values - in case there's doubt: answers for x = 2.1, y = 7.1

A. \(x^2y\) = 28 + a little

B. \(xy^2\) = 100 + a little

C. 5xy = about 75

D. \(\frac{4x^2y}{3}\) = = a little less than 40

E. \(\frac{x^2}{y}\)= about \(\frac{4}{7}\)

The whole numbers and the decimals behaved exactly the same way. These numbers are not close either.

Answer B

Kudos [?]: 396 [0], given: 640

Expert Post
1 KUDOS received
Target Test Prep Representative
User avatar
S
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 1922

Kudos [?]: 1010 [1], given: 3

Location: United States (CA)
If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < [#permalink]

Show Tags

New post 19 Oct 2017, 10:19
1
This post received
KUDOS
Expert's post
Bunuel wrote:
If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < y < 8, which of the following expressions will have the largest value?

A. \(x^2y\)

B. \(xy^2\)

C. 5xy

D. \(\frac{4x^2y}{3}\)

E. \(\frac{x^2}{y}\)


First, notice that y is greater than x, and y^2 is significantly greater than x^2. This observation allows us to immediately suspect that B is the correct answer because it is the only choice that contains y^2. We can immediately rule out choices A, C, and E without doing any calculations because each of them contains the relatively small value of x^2, and none of them contain the large value y^2.

Let’s consider choice D, which multiplies the relatively small value of (x^2)(y) by 4/3, which makes it larger. But multiplication by 4/3 is not enough to make (x^2)(y)(4/3) greater than choice B.

Answer: B
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Kudos [?]: 1010 [1], given: 3

Manager
Manager
User avatar
B
Joined: 09 Aug 2017
Posts: 59

Kudos [?]: 8 [0], given: 18

Location: United States
Concentration: Technology
GMAT 1: 640 Q44 V33
GMAT 2: 630 Q47 V29
WE: Research (Investment Banking)
CAT Tests
Re: If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 < [#permalink]

Show Tags

New post 23 Oct 2017, 07:40
I got B, but perhaps I was totally inefficient which might be a cause for my propensity to make lots of stupid mistakes.
-Even though x cannot equal 3 and y cannot equal 8, they can be infinitely close to each number. So I used the outer bounds of each range and plugged them into each number. B produced the largest result.
-For A, I got 72.
-For B, I got 192.
-For C, I got 120
-For D, I got 96,
-E, I didn't calculate because it's some small fraction.

-This problem could have been made a lot harder with the inclusion of negatives as we would have to determine whether certain exponents produce a negative or positive.
_________________

I'd love to hear any feedback or ways to improve my problem solving. I make a lot of silly mistakes. If you've had luck improving on stupid mistakes, I'd love to hear how you did it.

Also, I appreciate any kudos.

Kudos [?]: 8 [0], given: 18

Re: If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 <   [#permalink] 23 Oct 2017, 07:40
Display posts from previous: Sort by

If x is a number satisfying 2 < x < 3 and y is a number satisfying 7 <

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.