Question #f0f34

1 Answer
Jan 30, 2018

#120#

Explanation:

#"using the definition of "^nP_r#

#•color(white)(x)^nP_r=(n!)/((n-r)!)#

#"where "n! =n(n-1)(n-2) ...... xx3xx2xx1#

#rArr^5P_5=(5!)/((5-5)!)=(5!)/(0!)#

#" note that "[0! =1]#

#rArr^5P_5=(5xx4xx3xx2xx1)/1=120#