Target Test Prep 20% Off Flash Sale is on! Code: FLASH20

Redeem
Target Test Prep
5-Day Free Trial
5-day free, full-access trial TTP

Available with Beat the GMAT members only code

MORE DETAILS
Target Test Prep
Magoosh
Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

MORE DETAILS
Magoosh

Exponents and Scientific Notation

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 158
Joined: Mon Nov 02, 2009 5:49 pm
Thanked: 2 times
Followed by:3 members

Exponents and Scientific Notation

by tonebeeze » Sun Aug 21, 2011 2:42 pm
Can some please show their work (step-by step). Thanks!

Source: OG 10 #136 PS

if (0.0015 x 10^m) / (0.03 x 10^k) = (5 x 10^7), then m - k = ?

a. 9
b. 8
c. 7
d. 6
e. 5

OA = a
Our collective understanding of the GMAT grows through research, contribution, and teamwork. If you found a problem or comment challenging, helpful, or encouraging, please consider hitting the THANKS button!
Top
Master | Next Rank: 500 Posts
Posts: 160
Joined: Fri May 30, 2008 7:10 pm
Thanked: 10 times
GMAT Score:600

by dendude » Sun Aug 21, 2011 3:30 pm
Rewriting in form of power of 10
(15 x 10^m-4)/(3 x 10^k-2) = 5 x 10^7
5 x 10^m-4-k+2 = 5 x 10^7
Equating powers of 10,
m-4-k+2 = 7
m-k-2 = 7
m-k = 9

Ans A
Top
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Mon Aug 22, 2011 4:44 am
tonebeeze wrote:Can some please show their work (step-by step). Thanks!

Source: OG 10 #136 PS

if (0.0015 x 10^m) / (0.03 x 10^k) = (5 x 10^7), then m - k = ?

a. 9
b. 8
c. 7
d. 6
e. 5

OA = a
(0.0015 * 10^m) / (0.03 * 10^k) = (5 * 10^7)

(15 * 10^(-4) * 10^m) / (3 * 10^(-2) * 10^k) = (5 * 10^7)

5 * 10^(-2) * 10^(m-k) = 5 * 10^7

10^(m-k) = 10^9

m-k = 9.

The correct answer is A.
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
Post new topic Post Reply
• Page 1 of 1