Is the integer z divisible by 3?
(1) The LCM of z and 12 is 12
(2) The LCM of z and 15 is 45.
What's the best way to determine whether statement 1 is sufficient?
OA B
Target Test Prep is 20% off right now!
Use code FLASH20
Available with Beat the GMAT members only code
MORE DETAILS
Is the integer z divisible by 3?
This topic has expert replies
-
BTGmoderatorDC
- Moderator
- Posts: 7187
- Joined: Thu Sep 07, 2017 4:43 pm
- Followed by:23 members
GMAT/MBA Expert
-
Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7263
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
We need to determine whether z/3 = integerlheiannie07 wrote:Is the integer z divisible by 3?
(1) The LCM of z and 12 is 12
(2) The LCM of z and 15 is 45.
Statement One Alone:
The LCM of z and 12 is 12.
Using the information in statement one, we see that z could equal 1, 2, 3, 4, 6, or 12 since the LCM of any of these numbers and 12 is 12. Furthermore, we cannot determine whether z/3 is an integer. For instance, if z = 1, then z/3 is not an integer, but if z = 3, then z/3 is an integer. Statement one alone is not sufficient to answer the question. We can eliminate answer choices A and D.
Statement Two Alone:
The LCM of z and 15 is 45.
Using the information in statement two, we see that z could only equal 9 or 45 since these two numbers are the only numbers that produce an LCM of 45 when paired with 15. If z = 9, then z/3 is an integer. If z = 45, then z/3 is an integer as well. Statement two alone is sufficient to answer the question.
Answer: B
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
-
BTGmoderatorDC
- Moderator
- Posts: 7187
- Joined: Thu Sep 07, 2017 4:43 pm
- Followed by:23 members
Thanks a lot!Scott@TargetTestPrep wrote:We need to determine whether z/3 = integerlheiannie07 wrote:Is the integer z divisible by 3?
(1) The LCM of z and 12 is 12
(2) The LCM of z and 15 is 45.
Statement One Alone:
The LCM of z and 12 is 12.
Using the information in statement one, we see that z could equal 1, 2, 3, 4, 6, or 12 since the LCM of any of these numbers and 12 is 12. Furthermore, we cannot determine whether z/3 is an integer. For instance, if z = 1, then z/3 is not an integer, but if z = 3, then z/3 is an integer. Statement one alone is not sufficient to answer the question. We can eliminate answer choices A and D.
Statement Two Alone:
The LCM of z and 15 is 45.
Using the information in statement two, we see that z could only equal 9 or 45 since these two numbers are the only numbers that produce an LCM of 45 when paired with 15. If z = 9, then z/3 is an integer. If z = 45, then z/3 is an integer as well. Statement two alone is sufficient to answer the question.
Answer: B
