GRE Prep 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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Which of the following is equal to the average (arithmetic mean) of
[#permalink]
04 Aug 2021, 06:56
04 Aug 2021, 06:56
1
Expert Reply
00:00
Question Stats:
89% (00:40) correct
10% (00:47) wrong based on 28 sessions
Hide Show timer Statistics
Which of the following is equal to the average (arithmetic mean) of \((x+3)^2\) and \((x-3)^2\) ?
A. \(x^2\)
B. \(x^2+3
\)
C. \(x^2+9\)
D. \(x^2+3x\)
E. \(x^2+9x
\)
A. \(x^2\)
B. \(x^2+3
\)
C. \(x^2+9\)
D. \(x^2+3x\)
E. \(x^2+9x
\)
Re: Which of the following is equal to the average (arithmetic mean) of
[#permalink]
04 Aug 2021, 07:00
04 Aug 2021, 07:00
1
(x + 3)^2 = x^2 + 9 + 6x
(x - 3)^2 = x^2 + 9 - 6x
((x + 3)^2 + (x - 3)^2)/2 = 2 * (x^2 + 9)/2 = (x^2 + 9)
(x - 3)^2 = x^2 + 9 - 6x
((x + 3)^2 + (x - 3)^2)/2 = 2 * (x^2 + 9)/2 = (x^2 + 9)
Moderator
Joined: 02 Jan 2020
Status:GRE Quant Tutor
Posts: 1126
Given Kudos: 9
Location: India
Concentration: General Management
Schools: XLRI Jamshedpur, India - Class of 2014
GMAT 1: 700 Q51 V31
GPA: 2.8
WE:Engineering (Computer Software)
Re: Which of the following is equal to the average (arithmetic mean) of
[#permalink]
04 Aug 2022, 00:04
04 Aug 2022, 00:04
Theory
The average (arithmetic mean) of \((x+3)^2\) and \((x-3)^2\)
Average = \(\frac{Sum}{2}\) = \(\frac{(x+3)^2 + (x-3)^2 }{ 2}\) = \(\frac{x^2 + 2*x*3 + 3^2 + x^2 - 2*x*3 + 3^2}{ 2}\) =\(\frac{ 2*(x^2 + 9)}{2}\) = \(x^2 + 9\)
So, Answer will be C.
Hope it helps!
Watch the following video to Learn the Basics of Statistics
- ➡ Average = Sum of all the Values / Total Number of Values
The average (arithmetic mean) of \((x+3)^2\) and \((x-3)^2\)
Average = \(\frac{Sum}{2}\) = \(\frac{(x+3)^2 + (x-3)^2 }{ 2}\) = \(\frac{x^2 + 2*x*3 + 3^2 + x^2 - 2*x*3 + 3^2}{ 2}\) =\(\frac{ 2*(x^2 + 9)}{2}\) = \(x^2 + 9\)
So, Answer will be C.
Hope it helps!
Watch the following video to Learn the Basics of Statistics
