Tanya prepared 4 different letters to be sent to 4 different addresses. For each letter, she prepared an envelope with its correct address. If the 4 letters are to be put into the 4 envelopes at random, what is the probability that only 1 letter will be put into the envelope with its correct address? Pick one:
A) 1/24  B) 1/8  C) 1/4  D) 1/3  E) 3/8
Total # of ways of choosing envelopes=4!=24.   Only one letter in the right envelope: 4(# of envelopes)*2(# of ways possible to arrange 3 letters incorrectly in the envelopes, when one is correct)   ABC1/3(envelopes)   AC1/3B(letters)   A1/3BC(letters)   (When A is in the right envelope other three have only 2 possible incorrect arrangements)   As we have 4 letters, total # of ways   4*2= 
<gadget id="calculator">  4*2</gadget>
<output>8</output>
8   P(C=1)=8/24=1/3   Answer:1/3
<result>D</result>
Tanya prepared 4 different letters to be sent to 4 different addresses. For each letter, she prepared an envelope with its correct address. If the 4 letters are to be put into the 4 envelopes at random, what is the probability that only 1 letter will be put into the envelope with its correct address?