SOLUTION: Suppose that 5 thank-you notes are written and 5 envelopes are addressed. Accidentales, the notes are randomly inserted into the envelopes and mailed without checking the addressed

Algebra ->  Permutations -> SOLUTION: Suppose that 5 thank-you notes are written and 5 envelopes are addressed. Accidentales, the notes are randomly inserted into the envelopes and mailed without checking the addressed      Log On

The number of all possible permutations of 5 notes (= the number of all possible outcomes) is  5! = 5*4*3*2*1 = 120.


Of them, only one is matching.


So the probability under the question is  .