Question

A teacher has to divide his class of 12 students into 4 different groups, so that each group has exactly three student (a) how many ways can this be divided (b) two of the 12 students are twins, and must be in the same group. Now how many ways can the group be formed by the teacher

Answer 1

`(a).\frac{12!}{(3!)^4.\text{ 4!}}=\text{ 15400 }`