• NEW! FREE Beat The GMAT Quizzes
    NEW! FREE Beat The GMAT Quizzes
    NEW! FREE Beat The GMAT Quizzes
    Hundreds of Questions Highly Detailed Reporting Expert Explanations TAKE A FREE GMAT QUIZ
  • 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

If x + x^2 + x^3 = 27, then the average (arithmetic mean)

This topic has 1 expert reply and 1 member reply

If x + x^2 + x^3 = 27, then the average (arithmetic mean)

Post

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Difficult



If x + x^2 + x^3 = 27, then the average (arithmetic mean) of x + x^2 + x^3 + x^4 is equal to which of the following?

A. 3
B. 3x
C. 7x
D. 9
E. 9x

OA=C

Source: Veritas Prep

  • +1 Upvote Post
  • Quote
  • Flag
Legendary Member
Joined
10 May 2014
Posted:
1079 messages
Followed by:
23 members
Upvotes:
205
Post
M7MBA wrote:
If x + x^2 + x^3 = 27, then the average (arithmetic mean) of x + x^2 + x^3 + x^4 is equal to which of the following?

A. 3
B. 3x
C. 7x
D. 9
E. 9x

OA=C

Source: Veritas Prep
Average = (x + x^2 + x^3 + x^4)/4 = x (1 + x+ x^2 + x^3 )/4 = x(1+27)/4 = 28x/4 = 7x

Answer: Option C

_________________
Bhoopendra Singh & Sushma Jha - Founder "GMATinsight"
Testimonials e-mail: info@GMATinsight.com I Mobile: +91-9999687183 / +91-9891333772
To register for One-on-One FREE ONLINE DEMO Class Call/e-mail
One-On-One Private tutoring fee - US$40 per hour & for FULL COURSE (38 LIVE Sessions)-US$1000

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post
[quote="GMATinsight"]
M7MBA wrote:
If x + x^2 + x^3 = 27, then the average (arithmetic mean) of x + x^2 + x^3 + x^4 is equal to which of the following?

A. 3
B. 3x
C. 7x
D. 9
E. 9x
We can PLUG IN THE ANSWERS, which represent the average of x + x² + x³ + x⁴.

Test B:
(x + x² + x³ + x⁴)/4 = 3x
Multiplying both sides by 4, we get:
x + x² + x³ + x⁴ = 12x
Dividing both sides by x, we get:
1 + x + x² + x³ = 12
Substituting x+x²+x³=27 into 1+x+x²+x³ = 12, we get:
1 + 27 = 12
28 = 12

The right side needs to be greater.
Test C:
(x + x² + x³ + x⁴)/4 = 7x
Multiplying both sides by 4, we get:
x + x² + x³ + x⁴ = 28x
Dividing both sides by x, we get:
1 + x + x² + x³ = 28
Substituting x+x²+x³=27 into 1+x+x²+x³ = 28, we get:
1 + 27 = 28
28 = 28
Success!

The correct answer is C.

_________________
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.
  • Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • 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
  • 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
  • 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
  • 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
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh

Top First Responders*

1 Ian Stewart 57 first replies
2 Brent@GMATPrepNow 31 first replies
3 Jay@ManhattanReview 29 first replies
4 GMATGuruNY 20 first replies
5 ceilidh.erickson 15 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 Scott@TargetTestPrep

Target Test Prep

211 posts
2 image description Max@Math Revolution

Math Revolution

88 posts
3 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

70 posts
4 image description Ian Stewart

GMATiX Teacher

65 posts
5 image description GMATGuruNY

The Princeton Review Teacher

39 posts
See More Top Beat The GMAT Experts