GMAT Changed on April 16th - Read about the latest changes here

 It is currently 23 Apr 2018, 00:53

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

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by

Author Message
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 44617
In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by [#permalink]

Show Tags

12 Mar 2018, 21:59
Expert's post
1
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

72% (00:35) correct 28% (00:10) wrong based on 45 sessions

HideShow timer Statistics

In the formula $$a=b^2c$$, if b is multiplied by 2 and c is multiplied by 3, then $$a$$ must be multiplied by

A. 4
B. 6
C. 9
D. 12
E. 18
[Reveal] Spoiler: OA

_________________
Math Expert
Joined: 02 Sep 2009
Posts: 44617
Re: In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by [#permalink]

Show Tags

12 Mar 2018, 22:02
Bunuel wrote:
In the formula $$a=b^2c$$, if b is multiplied by 2 and c is multiplied by 3, then $$a$$ must be multiplied by

A. 4
B. 6
C. 9
D. 12
E. 18

7. Algebra

Check below for more:
ALL YOU NEED FOR QUANT ! ! !
_________________
SVP
Joined: 08 Jul 2010
Posts: 2067
Location: India
GMAT: INSIGHT
WE: Education (Education)
Re: In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by [#permalink]

Show Tags

13 Mar 2018, 05:02
Bunuel wrote:
In the formula $$a=b^2c$$, if b is multiplied by 2 and c is multiplied by 3, then $$a$$ must be multiplied by

A. 4
B. 6
C. 9
D. 12
E. 18

$$a=b^2c$$

if b is multiplied by 2 and c is multiplied by 3,

$$a_new=(2b)^2(3c)$$

$$a_new=12(b)^2(c)$$

i.e. a Must be multiples by 12

_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 3396
Location: India
GPA: 3.5
Re: In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by [#permalink]

Show Tags

13 Mar 2018, 07:45
Bunuel wrote:
In the formula $$a=b^2c$$, if b is multiplied by 2 and c is multiplied by 3, then $$a$$ must be multiplied by

A. 4
B. 6
C. 9
D. 12
E. 18

Plug in b = 2 and c = 3

So, $$a = b^2c$$ , ie $$a = 2^2*3$$

Hence, answer must be (D) 12
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

Director
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 726
Location: India
GMAT 1: 480 Q38 V22
GPA: 3.01
WE: Engineering (Consulting)
In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by [#permalink]

Show Tags

13 Mar 2018, 23:54
Bunuel wrote:
In the formula $$a=b^2c$$, if b is multiplied by 2 and c is multiplied by 3, then $$a$$ must be multiplied by

A. 4
B. 6
C. 9
D. 12
E. 18

a = b^2

Multiplying b by 2 we get 2b

Multiplying c by 3 we get 3c

Now, a = (2b)^2 * 3c

a = 12b^2 * c

a needs to be multiplied by 12 (D).
_________________

"Success is not as glamorous as people tell you. It's a lot of hours spent in the darkness."

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 2447
Location: United States (CA)
Re: In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by [#permalink]

Show Tags

14 Mar 2018, 16:01
Bunuel wrote:
In the formula $$a=b^2c$$, if b is multiplied by 2 and c is multiplied by 3, then $$a$$ must be multiplied by

A. 4
B. 6
C. 9
D. 12
E. 18

If b is multiplied by 2 and c is multiplied by 3, then we will have (2b)^2 * (3c) = 12b^2 * c, which is 12 times its original value. Since the right hand of the original equation has increased by a factor of 12, we must multiply the left side of the equation by 12 as well.

_________________

Scott Woodbury-Stewart
Founder and CEO

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

e-GMAT Representative
Joined: 04 Jan 2015
Posts: 1001
In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by [#permalink]

Show Tags

19 Mar 2018, 11:35

SOLUTION

We are given:
• $$a$$= $$b^2$$ c

If we multiply $$b$$ by $$2$$ and $$c$$ by $$3$$, then $$b$$ becomes $$2b$$ and $$c$$ becomes $$3c$$.
Thus, the new value of $$a$$ is equal to:

• =$$(2b)^2$$ *$$(3c)$$
• =$$4*$$$$b^2$$*$$3*c$$
• = $$12$$* ($$b^2$$ *$$c$$)
• =$$12*a$$
Therefore, $$a$$ must be multiplied by $$12$$.

_________________

| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

In the formula a=b^2c, if b is multiplied by 2 and c is multiplied by   [#permalink] 19 Mar 2018, 11:35
Display posts from previous: Sort by