1)How many four letter words can be formed from the word proportion?
2)How many committees of 9 people can be chosen from 12, if two certain people must never be in the same committee?
1) p is repeated twice, as is r, and o is repeated three times
so would it be 10C4 / (2!2!3!) to get rid of the double ups?
lets say 1 is taken out, u have 11C9, and the same if two was taken out 11C9, and for the case where they are both together:10C9??
I need some help with this one.