numere pare: 2/4/6/8/10/12/14/16/18/20/22/24/26/28/30 adica is 21 numere
probabilitatea= numar cazuri favorabile/nr cazuri totale
probabilitatea=21/30=7/10
si numere compuse: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 27, 28, 30 ..... adica 18 nr compuse
probabilitatea=18/30=3/5