You have to define “majority” of the delegates of eight (8) states.
A number higher than 50% would create a majority.
So if there are 24 delegates in a State, having 12 pledged delegates would NOT be a majority, while 13 would.
As of this morning, it appears as if Trump has seven contests (SC,AL,GA,HI,MA,MS,TN) and Cruz has four (ID,KS,ME,TX) that qualify. Rubio has one (PR).