Question
Jen,amy,linda,max and jenny are compteting to fill two remaining spots on the chess team. How mant different combinations are possible for filling the two spots?
120,60,20,or 10
120,60,20,or 10
Answers
PsyDAG
Let s = spots and n = number of students
n! = "n factorial" = product of all numbers n or less
P = n!/s!(n-s)! = 5!/2!(5-2)!
5! = 5 * 4 * 3 * 2 *1 = 120
2! = 2 * 1 = 2
(5-2)! = 3! = 3 * 2 * 1 = 6
P = 120/12 = 10
n! = "n factorial" = product of all numbers n or less
P = n!/s!(n-s)! = 5!/2!(5-2)!
5! = 5 * 4 * 3 * 2 *1 = 120
2! = 2 * 1 = 2
(5-2)! = 3! = 3 * 2 * 1 = 6
P = 120/12 = 10