i just took a diagnostic test so this question came up
If z is an integer multiple of both 6 and 10 then it must also be an integer multiple of
12
15
20
40
60
i thought the answer is 60
please explain what is wrong with 60.... thanks
but the OA is 15
numb properties from kaplan
This topic has expert replies
GMAT/MBA Expert
- Ian Stewart
- GMAT Instructor
- Posts: 2621
- Joined: Mon Jun 02, 2008 3:17 am
- Location: Montreal
- Thanked: 1090 times
- Followed by:355 members
- GMAT Score:780
If a number is an integer multiple of 6 and 10, the most you can say is that it's a multiple of the LCM of 6 and 10, i.e. of 30. If z must be a multiple of 30, z must be a multiple of 15, and B is the correct answer.
If you are wondering why 60 is not the correct answer, note that z could be 30 here. 30 is a multiple of both 6 and 10, but is not a multiple of 60.
If you are wondering why 60 is not the correct answer, note that z could be 30 here. 30 is a multiple of both 6 and 10, but is not a multiple of 60.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com
ianstewartgmat.com
ianstewartgmat.com