Probability of Envelopes

I need assistance with following problem along with steps to arrive at the solution/answer.

Three envelopes are addressed for 3 secret letters written in invisible ink. A secretary randomly places each of the letters in an envelope and mails them. What is the probability that at least 1 person receives the correct letter?

Solution Summary

This is a probability problem regarding randomly mailed letters. The solution explains how to solve the problem and shows the answer through step by step calculation.