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

It is currently 25 Mar 2019, 23:44

Close

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
Your Progress

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.

Close

Request Expert Reply

Confirm Cancel

if a and b denote two prime numbers, is the product ab <10?

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

Hide Tags

 
Manager
Manager
User avatar
P
Joined: 17 Oct 2016
Posts: 242
Location: India
Concentration: General Management, Healthcare
GMAT 1: 640 Q40 V38
GMAT 2: 680 Q48 V35
GPA: 3.05
WE: Pharmaceuticals (Health Care)
Premium Member Reviews Badge CAT Tests
if a and b denote two prime numbers, is the product ab <10?  [#permalink]

Show Tags

New post 08 Mar 2019, 21:53
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

88% (01:06) correct 13% (01:29) wrong based on 24 sessions

HideShow timer Statistics

If a and b denote two prime numbers, is the product ab <10?

A. a is the smallest prime number

B. b < 8 and b > a

_________________
_____________________
Chasing the dragon
Intern
Intern
avatar
B
Joined: 19 Jan 2019
Posts: 48
if a and b denote two prime numbers, is the product ab <10?  [#permalink]

Show Tags

New post 08 Mar 2019, 23:20
Statement 1 - a is the smallest prime number.. a= 2... Nothing about b.. if b = 3
ab<10, if b= 7 , ab> 10
Not sufficient.

Statement 2 - b<8 and b>a
Same as statement 1, not sufficient...

Combining both statements won't help.. a= 2, and b > 2, if b= 3 answer is yes, if b= 13 , the answer is no... Therefore E is the right choice.

Posted from my mobile device
CEO
CEO
User avatar
V
Joined: 12 Sep 2015
Posts: 3523
Location: Canada
Re: if a and b denote two prime numbers, is the product ab <10?  [#permalink]

Show Tags

New post 09 Mar 2019, 10:38
Top Contributor
fitzpratik wrote:
If a and b denote two prime numbers, is the product ab <10?

A. a is the smallest prime number

B. b < 8 and b > a


Given: a and b denote two prime numbers

Target question: Is the product ab <10?

Statement 1: a is the smallest prime number
No information about b
Statement 1 is NOT SUFFICIENT

Statement 2: b < 8 and b > a
There are several values of a and b that satisfy statement 2. Here are two:
Case a: a = 2 and b = 3. In this case, ab = (2)(3) = 6. So, the answer to the target question is YES, ab IS less than 10
Case b: a = 2 and b = 7. In this case, ab = (2)(7) = 14. So, the answer to the target question is NO, ab is NOT less than 10
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
IMPORTANT: When testing possible cases, always check to see whether you can re-use possible cases from previous statements.
In this case, we can see that the two cases I tested for Statement 1 can be re-used for the statements COMBINED.
Case a: a = 2 and b = 3. In this case, ab = (2)(3) = 6. So, the answer to the target question is YES, ab IS less than 10
Case b: a = 2 and b = 7. In this case, ab = (2)(7) = 14. So, the answer to the target question is NO, ab is NOT less than 10
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer: E

Cheers,
Brent
_________________
Test confidently with gmatprepnow.com
Image
GMAT Club Bot
Re: if a and b denote two prime numbers, is the product ab <10?   [#permalink] 09 Mar 2019, 10:38
Display posts from previous: Sort by

if a and b denote two prime numbers, is the product ab <10?

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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®.