Last visit was: 23 Apr 2026, 10:20 It is currently 23 Apr 2026, 10:20
Home
Messages
Tests
Schools
Events
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,782
Own Kudos:
810,823
 [28]
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,782
Kudos: 810,823
 [28]
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 06 Apr 2015, 07:14
1
Kudos
Add Kudos
27
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

35% (medium)

Question Stats:

74% (01:49) correct 26% (02:16) wrong based on 740 sessions

History

Date
Time
Result
Not Attempted Yet
If \(f(x) = \frac{343}{x^3}\), what is the value of \(f(7x)* f(\frac{x}{7})\) in terms of f(x)?


(A) \(f(x^2)\)

(B) \((f(x))^2\)

(C) \(f(x^3)\)

(D) \((f(x))^3\)

(E) \(f(343x)\)


­
ShowHide Answer
Official Answer
B
User avatar
Harley1980
User avatar
Retired Moderator
Joined: 06 Jul 2014
Last visit: 14 Jun 2024
Posts: 997
Own Kudos:
6,769
 [1]
Given Kudos: 178
Location: Ukraine
Concentration: Entrepreneurship, Technology
GMAT 1: 660 Q48 V33
GMAT 2: 740 Q50 V40
GMAT 2: 740 Q50 V40
Posts: 997
Kudos: 6,769
 [1]
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 06 Apr 2015, 07:37
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x)?

(A) f(x^2)
(B) (f(x))^2
(C) f(x^3)
(D) (f(x))^3
(E) f(343x)


Kudos for a correct solution.
Show more

Firstly we should calculate result of f(7x)* f(x/7)

\(\frac{343}{(7x)^3}*\frac{343}{(x^3/7^3)} = \frac{343^2}{x^6}\)

After this calculations we see that this is result of formula raised to second power

And answer is B
User avatar
GMATinsight
User avatar
Major Poster
Joined: 08 Jul 2010
Last visit: 23 Apr 2026
Posts: 6,976
Own Kudos:
16,907
 [2]
Given Kudos: 128
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Products:
My Reviews
Expert
Expert reply
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
Posts: 6,976
Kudos: 16,907
 [2]
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 06 Apr 2015, 11:44
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x)?

(A) f(x^2)
(B) (f(x))^2
(C) f(x^3)
(D) (f(x))^3
(E) f(343x)


Kudos for a correct solution.
Show more

f(x) = 343/x^3
@x=7, f(7) = 343/7^3 = 1
@x=1, f(1) = 343/1^3 = 343
@x=49, f(49) = 343/49^3 = 1/343


Now f(7x)* f(x/7)
@x=7, f(7x)* f(x/7) = f(49)* f(1) = (1/343) x (343) = 1 = f(7) = [f(7)]^2 = [f(x)]^2

Answer: Option
Show Spoiler
B
User avatar
Zhenek
User avatar
Joined: 17 Mar 2015
Last visit: 08 Jun 2021
Posts: 104
Own Kudos:
300
Given Kudos: 4
Posts: 104
Kudos: 300
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 06 Apr 2015, 15:06
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Lets look at the function f(x) from a general point of view:
\(f(a*x) = \frac{343}{(a*x)^3} = \frac{1}{a^3}*\frac{343}{x^3} = \frac{1}{a^3}*f(x)\)
Now lets look at our question: F(7*x)*F(x/7). 7*x and x/7 contain reciprocal numbers 1/7 and 7, which will be reduced because \(\frac{7^3}{7^3} = 1\), leaving us with just a product of f(x) and f(x) thus leaving us with a f(x)^2 which matches option B.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,782
Own Kudos:
810,823
 [2]
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,782
Kudos: 810,823
 [2]
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 13 Apr 2015, 07:55
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x)?

(A) f(x^2)
(B) (f(x))^2
(C) f(x^3)
(D) (f(x))^3
(E) f(343x)


Kudos for a correct solution.
Show more

VERITAS PREP OFFICIAL SOLUTION:

to get f(a) given f(x), all you need to do is substitute x with a.

f(x) = 343/x^3

f(7x) = 343/(7x)^3 = 1/x^3

f(x/7) = 343/(x/7)^3 = 343*343/x^3

So we get f(7x) * f(x/7) = (1/x^3) * (343*343/x^3) = (343/x^3)^2

But we know that 343/x^3 = f(x)

So, f(7x) * f(x/7) = (f(x))^2

Answer(B)

There are other ways of solving this too:

Say x = 1, then f(1) = 343

f(7x)* f(x/7) = f(7)*f(1/7) = (343/7^3) * (343/(1/7)^3 = (343)^2

So f(7x)* f(x/7) = (f(1))^2
User avatar
JeffTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 04 Mar 2011
Last visit: 05 Jan 2024
Posts: 2,974
Own Kudos:
8,710
Given Kudos: 1,646
Status:Head GMAT Instructor
Affiliations: Target Test Prep
Expert
Expert reply
Posts: 2,974
Kudos: 8,710
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 29 Sep 2017, 10:19
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If \(f(x) = \frac{343}{x^3}\), what is the value of \(f(7x)* f(\frac{x}{7})\) in terms of f(x)?


(A) \(f(x^2)\)

(B) \((f(x))^2\)

(C) \(f(x^3)\)

(D) \((f(x))^3\)

(E) \(f(343x)\)


Kudos for a correct solution.
Show more

Notice that 343 = 7^3, so we can write f(x) = 343/x^3 as f(x) = 7^3/x^3 = (7/x)^3. Furthermore:

f(7x) = (7/(7x))^3 = (1/x)^3 = 1/x^3

and

f(x/7) = (7/(x/7))^3 = (49/x)^3 = 49^3/x^3.

So, f(7x) * f(x/7) = 1/x^3 * 49^3/x^3 = 49^3/x^6.

Notice that 49 = 7^2, so 49^3/x^6 = (7^2)^3/x^6 = 7^6/x^6 = (7/x)^6 = ((7/x)^3)^2. Since f(x) = (7/x)^3, ((7/x)^3)^2 = (f(x))^2.

Answer: B
avatar
hawesg
avatar
Joined: 24 Jan 2018
Last visit: 03 May 2018
Posts: 10
Own Kudos:
4
Given Kudos: 30
Posts: 10
Kudos: 4
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 24 Mar 2018, 19:15
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Stupid me, I wrote down - rather than * on my scratch paper, spent forever trying to figure out what I was missing. Straightforward if you are trying to do the actual question. 7^3 = 343 so the first one is 1/x^3 and the second part is 343/(x^3/343) which can be rearranged to 343/x^3 * 343/x^3
User avatar
sujoykrdatta
User avatar
Joined: 26 Jun 2014
Last visit: 22 Apr 2026
Posts: 587
Own Kudos:
1,191
 [1]
Given Kudos: 14
Status:Mentor & Coach | GMAT Q51 | CAT 99.98
GMAT 1: 740 Q51 V39
Expert
Expert reply
GMAT 1: 740 Q51 V39
Posts: 587
Kudos: 1,191
 [1]
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 28 Jul 2023, 10:46
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If \(f(x) = \frac{343}{x^3}\), what is the value of \(f(7x)* f(\frac{x}{7})\) in terms of f(x)?
(A) \(f(x^2)\)
(B) \((f(x))^2\)
(C) \(f(x^3)\)
(D) \((f(x))^3\)
(E) \(f(343x)\)
Kudos for a correct solution.
Show more

f(x) = 343/x^3

f(7x) * f(x/7) = \([\frac{343}{(7^3 * x^3)}] * [\frac{343}{(x^3/7^3)}]\)
= \([\frac{343}{(343*x^3)}] * [\frac{343 * 343}{x^3}]\)
= \([\frac{343^2}{(x^3)^2}]\) = \((\frac{343}{x^3})^2\)
= \((f(x))^2\)

Answer B
User avatar
Paras96
User avatar
Joined: 11 Sep 2022
Last visit: 30 Dec 2023
Posts: 456
Own Kudos:
337
Given Kudos: 2
Location: India
Paras: Bhawsar
GMAT 1: 590 Q47 V24
GMAT 2: 580 Q49 V21
GMAT 3: 700 Q49 V35
GPA: 3.2
WE:Project Management (Other)
GMAT 3: 700 Q49 V35
Posts: 456
Kudos: 337
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 29 Jul 2023, 06:33
Kudos
Add Kudos
Bookmarks
Bookmark this Post
On simplifying
(343/343x3) (343*343/x3) = (343/x3)^2

= (f(x))^2
User avatar
Malar95
User avatar
Joined: 29 Oct 2023
Last visit: 13 Jun 2024
Posts: 328
Own Kudos:
168
Given Kudos: 11
Location: Malaysia
Posts: 328
Kudos: 168
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 02 Jan 2024, 04:26
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Im not sure if this is right but my fast method when I wrote out the equation and I saw what happened to be a pattern that got me to the right answer was that the 7 cancels out each other and others just adds up to a square. Mental math when I saw the pattern. Didnt time myself but got it within 30 sec prob.
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,966
Own Kudos:
1,117
Posts: 38,966
Kudos: 1,117
If f(x) = 343/x^3, what is the value of f(7x)* f(x/7) in terms of f(x) 24 Mar 2025, 08:47
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Bunuel
Math Expert
109782 posts
Krunaal
Tuck School Moderator
853 posts