BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

OG 13th edition #9 - Arithmetic

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 97
Joined: Mon Aug 04, 2014 5:39 pmFollowed by: 2 members
Thanked: 1 times
by lucas211 » Mon May 30, 2016 12:50 pm
Hello BTG

would appreciate a little help on the following question:


Image

thanks in advance
Last edited by lucas211 on Tue May 31, 2016 10:08 am, edited 1 time in total.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 410
Joined: Fri Mar 13, 2015 3:36 amFollowed by: 8 members
Location: Worldwide
Thanked: 120 times
GMAT Score:770

by OptimusPrep » Mon May 30, 2016 7:53 pm
lucas211 wrote:Which of the following is the value of √3√0,000064 ?

A) 0,004
B) 0,008
C) 0,02
D) 0,04
E) 0,2

thanks in advance
The problem statement is very misleading. Make sure you type the problem correctly

(3√0,000064)^(1/2) Or [(0.000064)^(1/3) ]^(1/2)

Start from the inner most value.

0.000064 = 64/1000000
(0.000064)^(1/3) = 4/100
{(0.000064)^(1/3) ]^(1/2) = (4/100)^(1/2) = 2/10

Correct Option: E
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 97
Joined: Mon Aug 04, 2014 5:39 pmFollowed by: 2 members
Thanked: 1 times

by lucas211 » Tue May 31, 2016 10:09 am
The problem statement is very misleading. Make sure you type the problem correctly
Hi OptimusPrep

Thanks for the notice. I have updated the original post.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 40
Joined: Wed Aug 30, 2017 6:48 pm

by danielle07 » Thu Aug 31, 2017 3:54 am
Nice question. I am having hard time solving it. But thanks to the one who has solution to it
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
Legendary Member
Posts: 503
Joined: Thu Jul 20, 2017 9:03 amFollowed by: 15 members
Thanked: 86 times
GMAT Score:770

by ErikaPrepScholar » Thu Aug 31, 2017 6:09 am
When you run into a long and unpleasant decimal like the one here, it's a good idea to turn the decimal into a fraction with numbers that are easier to work with.

√(∛0.000064) = √(∛(64/100000))

We could reduce our fraction further, but we should recognize our numerator as one of the few cube roots we have memorized: 64 = 4^3. Similarly, looking at the number of zeros in our denominator, we can determine that 100000 is another easy cube: 100^3. So taking the cube root of both the numerator and denominator gives us:

√(∛(4^3/100^3)) = √(4/100)

Then we take the square root of both the numerator and denominator:

√(4/100) = 2/10

Converting that back into a decimal gives us 0.2, or answer choice E. Be careful not to trip at the finish line by picking a trap like answer choice C - keep track of your zeros!
Image

Erika John - Content Manager/Lead Instructor
https://gmat.prepscholar.com/gmat/s/

Get tutoring from me or another PrepScholar GMAT expert: https://gmat.prepscholar.com/gmat/s/tutoring/

Learn about our exclusive savings for BTG members (up to 25% off) and our 5 day free trial

Check out our PrepScholar GMAT YouTube channel, and read our expert guides on the PrepScholar GMAT blog
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Thu Aug 31, 2017 8:54 am
√(∛0.000064)

= √[ (64 * 10¯â�¶)¹"²Â³ ]

= √(4 * 10¯²)

= (4 * 10¯²)¹"²Â²

= 2 * 10¯¹

= 0.2.

The correct answer is E.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
GMAT Instructor
Posts: 2630
Joined: Wed Sep 12, 2012 3:32 pmFollowed by: 119 members
Location: East Bay all the way
Thanked: 625 times
GMAT Score:780

by Matt@VeritasPrep » Thu Aug 31, 2017 4:15 pm
√∛0.000064 =>

√∛64/1000000 =>

√∛(2�/10�) =>

√(2²/10²) =>

2/10
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 1462
Joined: Thu Apr 09, 2015 9:34 amFollowed by: 22 members
Location: New York, NY
Thanked: 39 times

by Jeff@TargetTestPrep » Sat Sep 02, 2017 6:25 am
lucas211 wrote:Hello BTG

would appreciate a little help on the following question:


Image
Let's review the notation first. When an exponent is a fraction, that exponent indicates taking a root. So, if we have for example 27^1/3, the 1/3 instructs us to take the cube root of 27, which is 3. Similarly, if the exponent were 1/2, as in 25^1/2, the 1/2 instructs us to take the square root of 25, which is 5.

To solve this question, we can refer to two rules:

1) If a decimal with a finite number of decimal places is a perfect cube, its cube root will have exactly one-third of the number of decimal places. Thus, a perfect cube decimal must have a number of decimal places that is a multiple of 3.

2) If a decimal with a finite number of decimal places is a perfect square, its square root will have exactly half of the number of decimal places. Thus, a perfect square decimal must have an even number of decimal places.

Let's look first at (0.000064)^1/3. The 1/3 instructs us to take the cube root of 0.000064. By rule number 1, the cube root of 0.000064 = 0.04. We were able obtain this value because 0.000064 has 6 DECIMAL PLACES and because the cube root of 64 is 4.

The problem now looks like this: (0.04)^1/2. The ½ instructs us to find the square root of 0.04. By rule number 2, the square root of 0.04 = 0.2. We were able to obtain this value because 0.04 has 2 DECIMAL PLACES and the square root of 4 is 2.

Answer: E

Jeffrey Miller
Head of GMAT Instruction
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1