If p,s, and t are positive prime numbers, what is the value : DS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 19 Jan 2017, 14:46

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 p,s, and t are positive prime numbers, what is the value

Author Message
Manager
Joined: 23 Mar 2008
Posts: 219
Followers: 3

Kudos [?]: 143 [0], given: 0

If p,s, and t are positive prime numbers, what is the value [#permalink]

Show Tags

04 Jun 2008, 12:19
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions

HideShow timer Statistics

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

If p,s, and t are positive prime numbers, what is the value of p^3 * s^3 * t^3?
1) p^3 *st=728
2) t=13
Manager
Joined: 31 Oct 2007
Posts: 116
Followers: 1

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

Show Tags

04 Jun 2008, 14:51
Quote:
If p,s, and t are positive prime numbers, what is the value of p^3 * s^3 * t^3?
1) p^3 *st=728
2) t=13

To calculate we need p,q and t
A- Alone not sufficient.
B- Alone not sufficient
But if you combine it togeter
p^3 * s = 728/13=56,

Now, p must be 2, since 1 or 3 wont work. So p=2, t=13 and s=7 Answer = C
_________________

Many people dream, but some wake up and work towards it.

Director
Joined: 23 Sep 2007
Posts: 789
Followers: 5

Kudos [?]: 185 [0], given: 0

Show Tags

04 Jun 2008, 16:51
A

(p^3)*(st) = 728 = 2^3 * 5 * 13

p = 2
s = 5 or 13
t = 13 or 5

but the actual number of s and t does not matter because s^3 * t^3 = (st)^3
so (5*13)^3 is the same as (13*5)^3 = (st)^3 = s^3 * t^3
SVP
Joined: 29 Aug 2007
Posts: 2492
Followers: 67

Kudos [?]: 734 [0], given: 19

Show Tags

04 Jun 2008, 17:21
GMAT TIGER wrote:
puma wrote:
If p,s, and t are positive prime numbers, what is the value of p^3 * s^3 * t^3?
1) p^3 *st=728
2) t=13

is there anything missing?

sorry for the confusion:

1) p^3 *st=728
p^3 *st = 2x2x2x7x13

so p = 2, st = 7x13
suff...

2) t=13. nsf

C is a trap. so do not need st. 1 to answer. st 1 is suff....
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Director
Joined: 05 Jan 2008
Posts: 701
Followers: 5

Kudos [?]: 415 [0], given: 0

Show Tags

05 Jun 2008, 00:40
A for me.

Almost went for C

728/8=91 and 91 can be only 13*7 thus A
_________________

Persistence+Patience+Persistence+Patience=G...O...A...L

CEO
Joined: 29 Mar 2007
Posts: 2583
Followers: 19

Kudos [?]: 421 [0], given: 0

Show Tags

05 Jun 2008, 05:45
puma wrote:
If p,s, and t are positive prime numbers, what is the value of p^3 * s^3 * t^3?
1) p^3 *st=728
2) t=13

Notice that p^3 *st=728 is an even number.

Also notice that the units digit is 8. This means that p must be 2.

728/8 = 91. s and t are only 2 primes so 91 is divisible by ONly two numbers (other than 1 and itself).

No more work needed here.

2: dsnt help us.

A
Re: DS: prime numbers   [#permalink] 05 Jun 2008, 05:45
Display posts from previous: Sort by