MGMAT's Number Properties question (Chapter #1)

[ksear]

Hi everyone,

I need some help with this question as I'm really confused whether MGMAT's answer is correct (since I have read at several places in this forum that they have made some mistakes in terms of the correct answers). So here it is:

The instructions on top say that all variables in problems #1 through #12 are assumed to be integers unless otherwise indicated.

Question 9: If 6 is not a factor of d, is 12d divisible by 6?

MGMAT's answer and explanation: The fact that d is not divisible by 6 is irrelevant in this case. Since 12 is divisible by 6, 12d is also divisible by 6.

My concern: I think the answer is incorrect since it has been mentioned on top that variables are integers so if d is 0, then 12d becomes 0 hence it's not divisible by 6. Any feedback regarding this question is appreciated.

Kashif Sear.

[Rahul@gurome]

...
My concern: I think the answer is incorrect since it has been mentioned on top that variables are integers so if d is 0, then 12d becomes 0 hence it's not divisible by 6...

Every integer except zero itself is a divisor of zero.

[ksear]

so in other words, every number is a divisor of 0 (except o itself), be it 2, 100, 225 etc. ?

Pls confirm and thanks.

[Rahul@gurome]

so in other words, every number is a divisor of 0 (except o itself), be it 2, 100, 225 etc. ?

To be precise, every integer is divisor of zero (except zero itself), be it 2, 100, 225 etc.
The reasons I'm not saying "every number" are,

• (1) In general divisibility is defined for integers only.
  (2) 'Number' is a vague term in mathematics.

[ksear]

Yup I understand. Thanks.