What is the value of the integer K?
[1] K is a prime number between 40 and 50.
[2] The integer (K + 1) is divisible by exactly two different prime numbers.
[spoiler]Source: https://www.west.net/~stewart/gmat[/spoiler]
the integer K?
This topic has expert replies
- sanju09
- GMAT Instructor
- Posts: 3650
- Joined: Wed Jan 21, 2009 4:27 am
- Location: India
- Thanked: 267 times
- Followed by:80 members
- GMAT Score:760
The mind is everything. What you think you become. -Lord Buddha
Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001
www.manyagroup.com
Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001
www.manyagroup.com
- sumit.sinha
- Senior | Next Rank: 100 Posts
- Posts: 82
- Joined: Sat Aug 21, 2010 8:18 am
- Location: India
- Thanked: 5 times
(1) K = 41, 43 or 47 NOT SUFFICIENTsanju09 wrote:What is the value of the integer K?
[1] K is a prime number between 40 and 50.
[2] The integer (K + 1) is divisible by exactly two different prime numbers.
[spoiler]Source: https://www.west.net/~stewart/gmat[/spoiler]
(2) K =5 or 9.
Because 5+1 = 6 is divisible by exactly two different prime numbers 2 and 3.
Note: it is given (K + 1) is divisible by exactly two different prime numbers and NOT (K + 1) is ONLY divisible by exactly two different prime numbers. so there maybe other non-prime factors but we are not concerned about them.
and 9 +1 =10 is divisible by exactly two different prime numbers 2 and 5.
NOT SUFFICIENT
(1) ans (2) together - K = 43 or 47
Because if K = 41, K +1 = 42 is divisible by three different prime factors 2,3 and 7
if K = 43, K +1 = 44 is divisible by exactly two different prime factors 2 and 11
if K = 47, K +1 = 48 is divisible by exactly two different prime factors 2 and 3
NOT SUFFICIENT
CORRECT ANSWER (E)
Cheers,
Sumit
Sumit