Guild Wars 2

im looking to get the superior runes of the traveler set for my armor.
http://wiki.guildwars2.com/wiki/Rune_of_the_traveler
Rune #1,3,5 give magic find.
Do these numbers stack? So that I have 50% MF in the end?
Or to these numbers replace each other? so with 1 rune i have 10% MF, with 5 i have 25%?

Thanks in advance

yes you do get to 50% magic find