Suggest a group of 30 football players from which 8 are to be chosen as quarterbacks 7 as fullbacks, and 4 as centers. In how many manners can this selection be made? Now assume that the group of 30 football players includes 1S quarterbacks, 9 fullbacks, and 6 centers. Further suppose that the 8 quarterbacks to be selected must be chosen from among the 15 quarterbacks and likewise for the fullbacks and centers. How many different selections are possible?