Simple question:

* If x is an integer divisible by 15 but not divisible by 20, then x CANNOT be divisible by which of the following?

-------------6

-------------10

-------------12

-------------30

-------------150

The way I approached it is -- To be divisible by 15, but not by 20 would mean it needs to be divisible by 3, 5 but not 2, 4?

I know the answer but I am hoping someone explains to me in a simple way why/how?

Thanks,

uhsa

## Simple MATH question but having brain fart!

##### This topic has expert replies

I actually took an example of 30. 30 is divisible by 15 but not by 20.uhsa wrote:kvcpk,

That would mean that out of the answers given, 10, 30 and 150 are not divisible by 12?

Now 30 is div by 6,10,30 - ABD out

If I take x = 150, I see that x is also divisible by 150.

Hence picked C

you can also take a small number like 30, but you will have a problem with it when you go to 150. so pick the biggestest one from the options.

so 150/6 = 25

150/10 = 15

150/12 = a fraction

150/30 = 5

150/150=1.

so theres your answer.