When n is divided by 12, the remainder is 6. What is the remainder when n is divided by 6?

12 is the correct answer.

For some number to be divisible by 12 it has to be divisible by 6 and by 2.

we can write number n as:

n = 6 + 12*k where k is positive integer.

If we divide n by 12 we will get remainder 6 because 12*k part is divisible by 12.

The part 12*k is as said divisible by 12 which means it is divisible by 6 (as first stated) and it has remainder 0. That leaves us with 6/6 which again has 0 as remainder. That means that number n is divisible by 6

The answer is 0