Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 27 Sep 2016, 13:59

### 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

# PS - Exponents - OG 12

Author Message
Senior Manager
Joined: 30 Nov 2008
Posts: 491
Schools: Fuqua
Followers: 10

Kudos [?]: 258 [0], given: 15

PS - Exponents - OG 12 [#permalink]

### Show Tags

30 Mar 2009, 20:30
00:00

Difficulty:

(N/A)

Question Stats:

100% (01:01) correct 0% (00:00) wrong based on 15 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If $$t = \frac{1}{(2^9 * 5^3)}$$ is expressed as a terminating decimal, how many zeros will t have between the decimal point and the first nonzero digit to the right of the decimal point?

a) 3
b) 4
c) 5
d) 6
e) 9
Director
Joined: 01 Apr 2008
Posts: 898
Name: Ronak Amin
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 28

Kudos [?]: 579 [0], given: 18

Re: PS - Exponents - OG 12 [#permalink]

### Show Tags

30 Mar 2009, 21:16
B. ?
t = 1/(2^6 * 10^3) => Multiply 5s and 2s to get three 10s.
t = (1/2^6 ) * 10^-3. Now 1/64 = 0.01xxxx
So t will have 3 + 1 = 4 zeroes before 1.

mrsmarthi wrote:
If t = 1 / (2^9 * 5^3) is expressed as a terminating decimal, how many zeros will t have between the decimal point and the first nonzero digit to the right of the decimal point?

a) 3
b) 4
c) 5
d) 6
e) 9
Director
Joined: 25 Oct 2006
Posts: 648
Followers: 12

Kudos [?]: 458 [0], given: 6

Re: PS - Exponents - OG 12 [#permalink]

### Show Tags

31 Mar 2009, 00:11
1/10^3 * 1/2^6 = 0.001 * 0.01 = 0.00001

B.
_________________

If You're Not Living On The Edge, You're Taking Up Too Much Space

Senior Manager
Joined: 30 Nov 2008
Posts: 491
Schools: Fuqua
Followers: 10

Kudos [?]: 258 [0], given: 15

Re: PS - Exponents - OG 12 [#permalink]

### Show Tags

31 Mar 2009, 16:43
OA is B.

Director
Joined: 25 Oct 2008
Posts: 607
Location: Kolkata,India
Followers: 11

Kudos [?]: 694 [0], given: 100

Re: PS - Exponents - OG 12 [#permalink]

### Show Tags

01 Oct 2009, 17:29
I did'nt understand the last part//
Got it till here...1/2^6 x 10^-3
_________________

http://gmatclub.com/forum/countdown-beginshas-ended-85483-40.html#p649902

Intern
Joined: 24 Sep 2009
Posts: 9
Followers: 0

Kudos [?]: 1 [0], given: 0

Re: PS - Exponents - OG 12 [#permalink]

### Show Tags

02 Oct 2009, 09:27
tejal777 wrote:
I did'nt understand the last part//
Got it till here...1/2^6 x 10^-3

1/2^6 = 1/64 = 0.01XXX ;
10^-3=1/1000=0.001
so the product of these two numbers is 0.00001 so the answer is B
Senior Manager
Affiliations: ACA, CPA
Joined: 26 Apr 2009
Posts: 441
Location: Vagabond
Schools: BC
WE 1: Big4, Audit
WE 2: Banking
Followers: 5

Kudos [?]: 79 [0], given: 41

Re: PS - Exponents - OG 12 [#permalink]

### Show Tags

04 Oct 2009, 00:41
Another way to look at this problem is (assuming you know what 2^9 and 5^3 is) (512 and 125)

Both 1/2^9 and 1/5^3 will yield - 0.001xx and 0.00x

Take away : As long as the denominator in 1/xx is more than 101 and less than 1000, you will always have 0.00xx as the resulting decimal

Cheers!

tejal777 wrote:
I did'nt understand the last part//
Got it till here...1/2^6 x 10^-3

_________________

If you have made mistakes, there is always another chance for you. You may have a fresh start any moment you choose, for this thing we call "failure" is not the falling down, but the staying down.

Manager
Joined: 09 Oct 2009
Posts: 88
Schools: Ross(IN–full\$)
WE 1: Investment Bank
WE 2: Company in NYC
Followers: 3

Kudos [?]: 6 [0], given: 8

Re: PS - Exponents - OG 12 [#permalink]

### Show Tags

09 Oct 2009, 19:07
Another way to look at it is once you reach the poinwhere t = 1/64,000 you can set up a long division diagram with 1 underneath and 64,000 on the outside.

Then, place the decimal on top, and proceed to fill in zeros underneath until you reach a number that 64,000 goes into. In this case, you will get to 100,000 before you place a 1 above the last zero of 100,000, since 64,000 goes into 100,000 one time. Then just fill in the remaining zeroes above the division line and count them.

The procedure is diagrammed in the attached .jpg. The red zeroes get filled in one by one

Attachments

File comment: diagram of long division method

OG prob.JPG [ 2.31 KiB | Viewed 2740 times ]

Re: PS - Exponents - OG 12   [#permalink] 09 Oct 2009, 19:07
Display posts from previous: Sort by