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

 It is currently 05 May 2015, 11:25

### 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

# If d is a positive integer and f is the product of the first

Author Message
TAGS:
Manager
Joined: 10 Oct 2005
Posts: 113
Location: Hollywood
Followers: 0

Kudos [?]: 16 [0], given: 0

If d is a positive integer and f is the product of the first [#permalink]  31 Jan 2007, 05:20
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
If d is a positive integer and f is the product of the first 30 integers, what is the value if d?

(1) 10 (exp) d is a factor of f
(2) d > 6

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE
is sufficient.
EACH statement ALONE is sufficient
Statements (1) and (2) TOGETHER are NOT sufficient
_________________

The GMAT, too tough to be denied.
Beat the tough questions...

Senior Manager
Joined: 04 Jan 2006
Posts: 280
Followers: 1

Kudos [?]: 20 [0], given: 0

Re: DS - Product of the first 30 integers [#permalink]  31 Jan 2007, 06:58
TOUGH GUY wrote:
f is the product of the first 30 integers

Could anybody explain this?

If the question said that "f is product of the first 30 positive integer", I would assume f = 1 x 2 x 3 x ... x 30.
VP
Joined: 09 Jan 2007
Posts: 1045
Location: New York, NY
Schools: Chicago Booth Class of 2010
Followers: 10

Kudos [?]: 157 [0], given: 3

Re: DS - Product of the first 30 integers [#permalink]  31 Jan 2007, 11:29
TOUGH GUY wrote:
If d is a positive integer and f is the product of the first 30 integers, what is the value if d?

(1) 10 (exp) d is a factor of f
(2) d > 6

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE
is sufficient.
EACH statement ALONE is sufficient
Statements (1) and (2) TOGETHER are NOT sufficient

1) alone is not enough:
Since f=1x2x3x4x5x...x28x29x30
Multipying only the numbers that end in 2,5 and 0 you would get:
2x5x10x12x15x20x22x25x30 with several 10 factors there, like this it will be easier:
2
5
10=2x5
12=2x2x3
15=3x5
20=2x2x5
22=2x11
25=5x5
30=2x3x5

We have 8 numbers 2 and 7 numbers 5, so d can be from 1 do 7 by just taking these numbers...

2)d>6 alone is not enough either.

Putting them together: you have that d>6 from the 2) and that you have 7 possible numbers 10

PS) - the important thing is to watch for the 5s and not the 2s, because we have plenty of 2s...
SVP
Joined: 05 Jul 2006
Posts: 1519
Followers: 5

Kudos [?]: 115 [0], given: 39

the first 30 intigers is vague

intigers could be +ve or -ve or zero , tough guy need to revise the question
Current Student
Joined: 28 Dec 2004
Posts: 3391
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 13

Kudos [?]: 181 [0], given: 2

f=1*2*3*4*5....30

lets take the easy choice first...

statement 2) easy Insuff

statement 1) 10^d * m=f

well, lets see 10 has prime factors 5 and 2, so in the first 30 integers there are how many 2s? 30/2=15, 4 gives one more 2, 8 gives 2 more, 16 gives 3 more etc...

lets see how many 5s are there in first 30 integers...30/5=6, 25 gives us one more 5...so we have 7 fives...

now..if 10^d is a factor of F, then power of D cannot be greater than 7..
..
rewrite 10^d as 5^a 2^b, where the power of a determines d.

so..going back to statment 1) d can be anynumber from 0-7...Insuff

together..if d>6 then the only number that fits this is 7...

d=7..C is sufficient
Current Student
Joined: 28 Dec 2004
Posts: 3391
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 13

Kudos [?]: 181 [0], given: 2

yezz..it doesnt matter the sign of the integers...

yezz wrote:
the first 30 intigers is vague

intigers could be +ve or -ve or zero , tough guy need to revise the question
SVP
Joined: 05 Jul 2006
Posts: 1519
Followers: 5

Kudos [?]: 115 [0], given: 39

fresenha , y not zero to be the first of the 30 intigers
Director
Joined: 09 Aug 2006
Posts: 525
Followers: 2

Kudos [?]: 39 [0], given: 0

I second that Yezz. 1st 30 intergers is vague. Can anyone tell which is the one integer ? 0 or 1 or -1 ...?

Regards-
_________________

-Unstoppable force moves immovable objects...-

Current Student
Joined: 28 Dec 2004
Posts: 3391
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 13

Kudos [?]: 181 [0], given: 2

chief...if f was zero then statement 1 cannot be true..in gmat you have to know that the statements have to be true..

suppose f=0*1*2*3...29 then f=0

suppose d=0, then 10^0=1, which is not a factor of f;

yezz wrote:
fresenha , y not zero to be the first of the 30 intigers
SVP
Joined: 05 Jul 2006
Posts: 1519
Followers: 5

Kudos [?]: 115 [0], given: 39

WELL Fresinha ,

i thought that if 0 is a mutliple of any iniger then

if F = 0

THEN ANY NUMBER IS A FACTOR AND THUS STATMENT ONE REMAINS VALID
SVP
Joined: 05 Jul 2006
Posts: 1519
Followers: 5

Kudos [?]: 115 [0], given: 39

fresinha , any help on this one , i am really confused now?????
Current Student
Joined: 28 Dec 2004
Posts: 3391
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 13

Kudos [?]: 181 [0], given: 2

yezz...think of it this way if F=0 then you cannot say its a multiple of d, unless d=0...

refresh your defination of factors and multiples..

supposed m is a factor of n..then..2*m=n..or 3*m=n...in other words N is a multiple of m...

ok having established what factors and multiples means...

if F=0..then we have no Factors of F..zero has no factors other than itself.

Now..the statement 1) says 10^d is a factor of F...then we have to take this to b true. F cannot be 0 otherwise d would have to -infiniti..

now d can be zero and 10^0=1, F can be 1..but we need to rule this out..

so statment 2) does just that..it tell us that d is not zero..

if you need help with the rest of how to solve the question...PM me.

yezz wrote:
fresinha , any help on this one , i am really confused now?????
Similar topics Replies Last post
Similar
Topics:
38 If d is a positive integer and f is the product of the first 16 28 Jan 2012, 17:13
20 If d is a positive integer and f is the product of the first 69 10 Sep 2005, 11:58
If D is a positive number and F is the product of the first 1 25 Jan 2008, 10:41
If d is a positive factor and f is the product of the first 7 15 May 2006, 07:03
If d is a positive integer and f is the product of the first 5 22 Sep 2005, 20:54
Display posts from previous: Sort by