Hi all,

Let me show how I did it - and I am quite happy as I HATE number properties questions ...

First of all we have to start somewhere. And since this is a 3-digit number then it must be 100<x<999.

We also know that a=2b=2c. So, c will be 1/4 of a and b will be 1/2 of a. We are interested in a then!

In 999, the last digit is 9. So, a can never be 4 times 9, because it would be 36, making b 18. This is not a 3-digit number. In other words, we are looking for 2s to divide and multiply.

So, 8 is the greatest multiple of 2, from 1 to 9.

If a=8, then b=4 and c=2 --> x = 842

We cannot have a=2, as then c would be 1/2.

So, the lowest possibe a=4, making b=2 and c=1 --> x = 421.

Finally, 842 - 421 = 421,

ANS D