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

 It is currently 22 Mar 2019, 11:44

### 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

# M02-18

Author Message
TAGS:

### Hide Tags

Intern
Joined: 29 Sep 2017
Posts: 5

### Show Tags

10 Jul 2018, 10:45
how can you say on the basis of 2nd statement that the set consists of only negative or only positive numbers? The smallest and largest numbers will have the same sign. Excluding the smallest and largest numbers, other numbers can be mix of positive and negative.
Intern
Joined: 16 Jun 2018
Posts: 10

### Show Tags

13 Aug 2018, 01:35
(1) The product of any three integers in the set is negative. If the set consists of only 3 terms, then the set could be either {negative, negative, negative} or {negative, positive, positive}. If the set consists of more than 3 terms, then the set can only have negative numbers. Not sufficient.

(2) The product of the smallest and largest integers in the set is a prime number. Since only positive numbers can be primes, then the smallest and largest integers in the set must be of the same sign. Thus the set consists of only negative or only positive integers. Not sufficient.

(1)+(2) Since the second statement rules out {negative, positive, positive} case which we had from (1), then we have that the set must have only negative integers. Sufficient.

Bunuel

If the set consists of more than 3 terms, then the set can only have negative numbers.--?

Bunuel what if we have the set as -1 -1 1 1 in that case we do have a case of any 3 numbers turning up a negative result for -1 1 and 1.
How can all the numbers be negative if more than 3 terms exist?

Pls explain.
Math Expert
Joined: 02 Sep 2009
Posts: 53792

### Show Tags

13 Aug 2018, 01:57
psych77 wrote:
(1) The product of any three integers in the set is negative. If the set consists of only 3 terms, then the set could be either {negative, negative, negative} or {negative, positive, positive}. If the set consists of more than 3 terms, then the set can only have negative numbers. Not sufficient.

(2) The product of the smallest and largest integers in the set is a prime number. Since only positive numbers can be primes, then the smallest and largest integers in the set must be of the same sign. Thus the set consists of only negative or only positive integers. Not sufficient.

(1)+(2) Since the second statement rules out {negative, positive, positive} case which we had from (1), then we have that the set must have only negative integers. Sufficient.

Bunuel

If the set consists of more than 3 terms, then the set can only have negative numbers.--?

Bunuel what if we have the set as -1 -1 1 1 in that case we do have a case of any 3 numbers turning up a negative result for -1 1 and 1.
How can all the numbers be negative if more than 3 terms exist?

Pls explain.[/quote]

{-1, -1, 1, 1} does not satisfy the condition that the product of ANY three integers in the set is negative: -1*(-1)*1 = 1 = positive.

As explained in the solution, this could be true if:
a. the set consists of only 3 terms, then the set could be either {negative, negative, negative} or {negative, positive, positive}.
b. the set consists of more than 3 terms, then the set can only have negative numbers.
_________________
Intern
Joined: 20 May 2018
Posts: 17

### Show Tags

17 Sep 2018, 03:21
definitely a high quality question!
Manager
Joined: 12 Jul 2017
Posts: 95
GMAT 1: 570 Q43 V26
GMAT 2: 660 Q48 V34

### Show Tags

28 Nov 2018, 09:21
My earlier thinking:
When taking statement 1 & 2, can't we take
{ 1, -1 ,2 }
{-1, -1, 2}
Both will give us prime and also the product is negative.

Now, after reading the question 2-3 times :
the statement 2 says product of smallest and largest is prime
so consider { a, b , c } where a*c is prime so a < 0 then c < 0 then b has to be < 0 as product of three integers have to be prime.

This is a great question.
Manager
Joined: 22 Jun 2017
Posts: 178
Location: Argentina
Schools: HBS, Stanford, Wharton

### Show Tags

25 Feb 2019, 13:51
I think this is a high-quality question and I agree with explanation.
_________________

The HARDER you work, the LUCKIER you get.

Re M02-18   [#permalink] 25 Feb 2019, 13:51

Go to page   Previous    1   2   3   [ 46 posts ]

Display posts from previous: Sort by

# M02-18

Moderators: chetan2u, Bunuel

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.