2 for the 1st
2 for the 2nd
2 for the 3rd
and so on, so by the product rule of counting the total is their product:
Question 749359 in Permutations:
5-ways to choose 1st person
4-ways to choose the last (7)(6)(5)(4)(3)(2)(1) ways to choose middle people total: 20(7!)=10800 :) |