GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 19 Oct 2019, 15:43

### 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

# (3*10^20)(3*10^(-5))=

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58445

### Show Tags

24 Oct 2018, 00:15
00:00

Difficulty:

5% (low)

Question Stats:

93% (00:45) correct 7% (01:04) wrong based on 76 sessions

### HideShow timer Statistics

$$(3*10^{20})(3*10^{-5})=$$

A. $$9*10^{-100}$$

B. $$1*10^{-4}$$

C. $$9*10^{-4}$$

D. $$1*10^{15}$$

E. $$9*10^{15}$$

_________________
Senior Manager
Joined: 13 Jan 2018
Posts: 342
Location: India
Concentration: Operations, General Management
GMAT 1: 580 Q47 V23
GMAT 2: 640 Q49 V27
GPA: 4
WE: Consulting (Consulting)

### Show Tags

24 Oct 2018, 00:21
$$(3*10^{20})(3*10^{(-5)}) = 9 * 10^{15}$$

OPTION : E
_________________
____________________________
Regards,

Chaitanya

+1 Kudos

if you like my explanation!!!
e-GMAT Representative
Joined: 04 Jan 2015
Posts: 3074

### Show Tags

24 Oct 2018, 03:35

Solution

Given:
• We are given an expression, $$(3 * 10^{20})( 3 * 10^{-5})$$

To find:
• The value of the given expression

Approach and Working:
• $$(3 * 10^{20})( 3 * 10^{-5}) = (3 * 3) * (10^{20} * 10^{-5}) = 9 * 10^{(20-5)} = 9 * 10^{15}$$

Hence, the correct answer is Option E

_________________
VP
Joined: 31 Oct 2013
Posts: 1465
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)

### Show Tags

24 Oct 2018, 04:56
Bunuel wrote:
$$(3*10^{20})(3*10^{-5})=$$

A. $$9*10^{-100}$$

B. $$1*10^{-4}$$

C. $$9*10^{-4}$$

D. $$1*10^{15}$$

E. $$9*10^{15}$$

$$(3*10^{20})(3*10^{-5})=$$

$$(3*3) (10^{20}*10^{-5}$$

$$9 * 10^{10 + (-5)}$$

$$9 * 10^{15}$$

Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4774
Location: India
GPA: 3.5

### Show Tags

24 Oct 2018, 09:13
Bunuel wrote:
$$(3*10^{20})(3*10^{-5})=$$

A. $$9*10^{-100}$$

B. $$1*10^{-4}$$

C. $$9*10^{-4}$$

D. $$1*10^{15}$$

E. $$9*10^{15}$$

$$(3*10^{20})(3*10^{-5})$$

$$= 3^2*10^{20-5}$$

$$= 9*10^{15}$$; Answer must be (E)
_________________
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 )
Intern
Joined: 29 Oct 2012
Posts: 21

### Show Tags

24 Oct 2018, 09:47
Bunuel wrote:
$$(3*10^{20})(3*10^{-5})=$$

A. $$9*10^{-100}$$

B. $$1*10^{-4}$$

C. $$9*10^{-4}$$

D. $$1*10^{15}$$

E. $$9*10^{15}$$

$$(3*10^{20})(3*10^{-5})= 3*3*(10^{20-5}) = 9*(10^{15})$$

Manager
Joined: 24 Dec 2017
Posts: 185
Location: India
Concentration: Strategy, Real Estate
Schools: Johnson '21

### Show Tags

25 Oct 2018, 04:03
(3 x 10^20)
(3 x 10^(-5)) = 3 x 1/10^5
=> 3/10^5 x 3 x 10^20
=> 3 x 3 x 10^15
=>9 x 10^15

Hence E
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8109
Location: United States (CA)

### Show Tags

25 Oct 2018, 18:01
Bunuel wrote:
$$(3*10^{20})(3*10^{-5})=$$

A. $$9*10^{-100}$$

B. $$1*10^{-4}$$

C. $$9*10^{-4}$$

D. $$1*10^{15}$$

E. $$9*10^{15}$$

Simplifying, we have:

3 x 10^20 x 3 x 10^-5

3 x 3 x 10^20 x 10^-5

(3 x 3) x 10^(20 + (-5))

9 x 10^15

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Re: (3*10^20)(3*10^(-5))=   [#permalink] 25 Oct 2018, 18:01
Display posts from previous: Sort by