Question 32386
#1 P(player is not defective)= 48/50
 You did't say if the players were selected with replacement. 
I am assuming they were replaced.
   P(30 selections are made and none is defective)= (48/50)^30=0.29..
Now I am assuming they were not replaced:
   [48C30]/[50C30] = 0.155....
#2 12C3 = [12*11*10]/[1*2*3]= 220
#3 [4C2]/[52C2]= [(4*3)(1*2)]/[(52*51)/(1*2)]= 6/1326=0.0045...
Cheers,
Stan H.