Originally Posted by JillChang
Sorry I wasn't clear. Yes, it is YYZ-HKG-YYZ round trip, over 15K points.
Will I get this challenge-completed bonus mile (someone told me 100% of basic miles) when I complete the challenge with a single trip?
You get the 100% platinum bonus on the segment that qualifies you for that status, and every segment thereafter. In your case, you will only get the bonus in one direction -- on the HKG-YYZ segment. The concept of "trip" doesn't mean anything.