Question

There are 5 envelopes corresponding to 5 letters. If the letters are placed in random. What is the probability that atleast two letters are placed in wrong envelopes

Answer 1

Answer:

119/120

Step-by-step explanation:

There are 5 envelopes corresponding to 5 letters. If the letters are placed in random. What is the probability that atleast two letters are placed in wrong envelopes

if one letter ios placed in wrong envelope

then Letter placed in envelope of that Letter will also be wrong

=> if one letter is placed wrong then atleast two letters are placed in wrong Envelopes

=>  probability that atleast two letters are placed in wrong envelopes = 1 - All letters places Correctly

Total number of ways the letters can be placed in eneveloped = 5! = 120

All letters places Correctly = 1

=>  probability that atleast two letters are placed in wrong envelopes = 1 - 1/120  = 119/120

Answer 2

Answer:

5! - 1 / 5! = 119/120

Step-by-step explanation: