no. of ways of dividing 15 men and 15 women into 15 couples

Question

permutation and combination

Answer 1

15 * 15 = 225

14 * 14 = 196

13 * 13 = 169

12 * 12 = 144

11 * 11 = 121

10 * 10 = 100

 9 *  9 =  81

 8 *  8 =  64

 7 *  7 =  49

 6 *  6 =  36

 5 *  5 =  25

 4 *  4 =  16

 3 *  3 =   9

 2 *  2 =   4

 1 *  1 =   1

         ----

         1240

This a probability without replacement.  15 men and 15 women, then 14 men and 14 women, etc.