1. ## SAT question

All numbers divisible by both 4 and 15 are also divisible by which of the following?

A. 6
B. 8
C. 18
D. 24
E. 25

2. ## Re: SAT question

The LCM of 4 and 15 is 60.

So which of those numbers is a factor of 60?

3. ## Re: SAT question

6 thanks, so if a number is factor of a LCM of two number, they can divide evenly multiples of those two number
Originally Posted by e^(i*pi)
The LCM of 4 and 15 is 60.

So which of those numbers is a factor of 60?

4. ## Re: SAT question

Originally Posted by RK29
6 thanks, so if a number is factor of a LCM of two number, they can divide evenly multiples of those two number
Yes, that's it exactly. It also holds for the LCM of more than two numbers.

For example the LCM of 2,3 and 8 is 24 so any other factor of 24 will divide by multiples of 2,3 and 8

5. ## Re: SAT question

what's a quick way to find LCM and GCF? i am having hard time.

6. ## Re: SAT question

Originally Posted by RK29
what's a quick way to find LCM and GCF? i am having hard time.
LCM and GCF

Prime factors are the easiest way, the link above explains it better than I can

7. ## Re: SAT question

I learned that way when i was young, they complicated stuff over years