After the typist writes 12 letters and addresses 12 envelopes, she inserts the letters randomly into the envelopes (1 letter per envelope). What is the probability that exactly 1 letter is inserted in an improper envelope? Options:  A) 1/12  B) 0  C) 12/212  D) 11/12  E) 11/13
0   If one letter is in wrong envelope, the letter corresponding to that letter will also be in wrong envelope.   ANSWER:0
<result>B</result>
After the typist writes 12 letters and addresses 12 envelopes, she inserts the letters randomly into the envelopes (1 letter per envelope). What is the probability that exactly 1 letter is inserted in an improper envelope?