Rounding off numbers question

OK Guys just a simple question but i can get it through my head.

I want to round off this number to 3 significant digit

18.45056065

Now as far as i know, the rules are

if the two digits following the cutoffpoint is exactly 50 the precedding figure

is not altered if it is an even number.

So following this rule the right answer should be 18.4 right?

The right answer on my book is 18.5. Please help me out!! I cant seem to get why im getting the wron answer! perhaps the book is wrong?