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

 It is currently 22 Oct 2019, 10:04 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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.  If p and q are integers greater than zero, what is the value of pq?

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 58425
If p and q are integers greater than zero, what is the value of pq?  [#permalink]

Show Tags 00:00

Difficulty:   5% (low)

Question Stats: 86% (00:46) correct 14% (01:34) wrong based on 204 sessions

HideShow timer Statistics

If p and q are integers greater than zero, what is the value of pq?

(1) The least common multiple of p and q is 240.

(2) The greatest common factor of p and q is 8.

Kudos for a correct solution.

_________________
Manager  Joined: 26 Nov 2014
Posts: 84
If p and q are integers greater than zero, what is the value of pq?  [#permalink]

Show Tags

Bunuel wrote:
If p and q are integers greater than zero, what is the value of pq?

(1) The least common multiple of p and q is 240.

(2) The greatest common factor of p and q is 8.

Kudos for a correct solution.

St 1:

LCM of P & Q = 240,
P=60, Q=80 , or vice versa, LCM 240, PQ = 4800
P=30, Q=80 or vice versa, LCM 240, PQ = 2400
P=10, Q=240 or vice versa,LCM 240, PQ = 2400
P=8, Q=240 or vice versa, LCM 240, PQ = 1920
P=6, Q=240 or vice versa, LCM 240, PQ = 1440 ......

So many values. Not sufficient.

St 2:

GCF of P & Q = 8

P=8, Q=16 , GCF 8, PQ = 128
P=24, Q=40, GCF 8, PQ = 960
P=240, Q=8, GCF 8, PQ = 1920.....

Same here. Not sufficient.

Combine 1 & 2,
LCM of P * Q is 240, GCF is 8 only when P=240, Q=8 or vice versa
There PQ = 1920.

Ans C.
GMAT Club Legend  V
Joined: 12 Sep 2015
Posts: 4017
Re: If p and q are integers greater than zero, what is the value of pq?  [#permalink]

Show Tags

Bunuel wrote:
If p and q are integers greater than zero, what is the value of pq?

(1) The least common multiple of p and q is 240.

(2) The greatest common factor of p and q is 8.

Kudos for a correct solution.

Target question: What is the value of pq?

Statement 1: The least common multiple of p and q is 240.
This statement doesn't FEEL sufficient, so I'm going to TEST some values.There are several values of p and q that satisfy statement 1. Here are two:
Case a: p = 1 and q = 240, in which case pq = 240
Case b: p = 240 and q = 240, in which case pq = 240^2
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Aside: For more on this idea of plugging in values when a statement doesn't feel sufficient, you can read my article: http://www.gmatprepnow.com/articles/dat ... lug-values

Statement 2: The greatest common factor of p and q is 8
This statement doesn't FEEL sufficient either, so I'm going to TEST some values.
Case a: p = 8 and q = 8, in which case pq = 64
Case b: p = 8 and q = 16, in which case pq = 128
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
There's a nice rule that says (greatest common factor of y and x )(least common multiple of x and y) = xy
So, (8)(240) = pq
Since we can answer the target question with certainty, the combined statements are SUFFICIENT

Cheers,
Brent
_________________
Manager  Joined: 29 Jul 2015
Posts: 155
Re: If p and q are integers greater than zero, what is the value of pq?  [#permalink]

Show Tags

Bunuel wrote:
If p and q are integers greater than zero, what is the value of pq?

(1) The least common multiple of p and q is 240.

(2) The greatest common factor of p and q is 8.

Kudos for a correct solution.

Statement 1:
Doesn't provide any concrete values for p and q.
INSUFFICIENT

Statement 2:
Again, doesn't tell much about p and q.
INSUFFICIENT

Combining 1 and 2:
HCF*LCM= Product of the two given numbers.

or pq = 240*8 =1920
SUFFICIENT

Intern  Joined: 13 Nov 2014
Posts: 44
GMAT 1: 590 Q42 V29 GMAT 2: 630 Q47 V29 Re: If p and q are integers greater than zero, what is the value of pq?  [#permalink]

Show Tags

Individual statements are not sufficient. coz 240 LCM and 8 GCM can have multiple possibilities
hence
IMO C
_________________
-----------------------------------------
Consider Cudos if you like this post.
-----------------------------------------
Intern  Joined: 29 Mar 2015
Posts: 22
Re: If p and q are integers greater than zero, what is the value of pq?  [#permalink]

Show Tags

For any two numbers a and b:
$$a*b = gcd(a, b) * lcm(a, b)$$

$$p*q = 240 * 8 = 1920$$

Director  S
Joined: 12 Nov 2016
Posts: 699
Location: United States
Schools: Yale '18
GMAT 1: 650 Q43 V37 GRE 1: Q157 V158 GPA: 2.66
Re: If p and q are integers greater than zero, what is the value of pq?  [#permalink]

Show Tags

Bunuel wrote:
If p and q are integers greater than zero, what is the value of pq?

(1) The least common multiple of p and q is 240.

(2) The greatest common factor of p and q is 8.

Kudos for a correct solution.

Out of curiosity - has anybody actually seen this on an actually GMAT exam?

Anyways if you have the lcm and gcf of x and y then you have enough to know the product of x and y
Current Student B
Joined: 16 Jul 2017
Posts: 48
Location: United Kingdom
GMAT 1: 660 Q47 V34 GPA: 3.87
Re: If p and q are integers greater than zero, what is the value of pq?  [#permalink]

Show Tags

I learned a really helpful formula from a Magoosh lesson...
For any two integers, P & Q:
LCM = (P*Q)/GCF [where LCM = Lowest Common Multiple; GCF = Greatest Common Factor]

Using the above formula you can quickly deduce that Statements 1 and 2 are insufficient on their own, but sufficient together. Re: If p and q are integers greater than zero, what is the value of pq?   [#permalink] 22 Nov 2017, 12:53
Display posts from previous: Sort by

If p and q are integers greater than zero, what is the value of pq?

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne  