Four trumpet players’ instruments are mixed up, and the trumpets are given to the players just before a concert. What is the probability that no one gets his or her trumpet back?

Question

anonymous · Answer

I know that the answer is 3/8 but I don't know why. HELP!

anonymous · Answer

are you sure it's 3/8?

anonymous · Answer

total number of ways to distribute = 4!=4*3*2=24
no one gets the correct one = 3+3+3 (i.e., each one can have 3 other ones)
P=(3+3+3)/24=3*3/24=3/8