Talk:Last Whisper/@comment-41.212.12.214-20120521050325/@comment-114.72.227.209-20120602113433

For the armour penetration, you have to multiply the remainder of each reduction.

Last Whisper = 60% armour left.

Darius' E, 60% * 75% = 45% armour left.

Weapons Expertise mastery, 45% * 90% = 40.5% armour left.

So, Darius with a LW and that mastery would leave 40.5% of their armour intact, i.e. penetrating 59.5% of the opponent's armour.