Respuesta :

129 arrangements can be made 5 x 4 x 3 x 2 x 1= 120
slot meathod

5 lettters with 5slots

1st slot has 5 choices
2nd slot has 4 (1 went to first slot)
3rd slot has 3
2hd has 2
1st has 1

multiply them together
5*4*3*2*1=120

answer is 120 arangements