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

Redeem

Exponents and Scientific Notation

Expert replies
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!
Join the discussion
Source: — Problem Solving |

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
Join the discussion

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
Join the discussion