5 letters and 5 addresses are there then what is the probability that no single letter goes to the correct address......try and tell me answer with clear explanation....

• above formula is : n!(1/2! - 1/3! + 1/4!+ .......((-1)^n)/n! by putting : into this formula : 5! -76 /5! = 11/30
• 8 years agoHelpfull: Yes(10) No(2)
• Total No of ways in which at least one letter goes to the correct envelope is 5!(1-1/2!+1/3!-1/4!+1/5!)=76So the no of ways in which none of the letter goes into the correct envelope = 5! - 76=44So reqd probability = 44/120 =11/30
• 8 years agoHelpfull: Yes(6) No(5)
• here 1st letter can be put in any one of the 5 envelopes in 5 ways. 2nd letter can be put in any one of the 4 envelopes in 4 ways and so on then we have 5*4*3*2*1=120
  out of 120 only one is the correct way to do so therefore total incorrect ways=120-1=119.
• 8 years agoHelpfull: Yes(5) No(5)
• probabilty of no one go to currect place=1-all will go to currect place
  =1-(1/5*1/4*1/3*1/2*1/1)=1/120
• 8 years agoHelpfull: Yes(3) No(1)
• Question goes like this : Five letters are addressed to five different persons and the corresponding envelopes are prepared. The letters are put into the envelopes at random. What is the probability that no letter is in its proper envelope?
• 8 years agoHelpfull: Yes(2) No(0)
• So let the letters be : A B C D E and the corresponding envelopes are : a b c d e. Now A cannot go to a, so A can for example go to c. Then C has 4 options to go to: a , b, d, and e. The 1st has 2 choices, the 2nd has 3, the 3rd has 3, and the 4th has 3 choices. So there are 2 + 3 + 3 + 3 = 11 choices. Since A has 4 options to go to, the total is then : 11*4 = 44. And there are a total of 5! ways to do so. So then probability is : 44/120. This is perhaps easier to digest than using the full theorem.
  
• 8 years agoHelpfull: Yes(1) No(2)
• Or we can directly put this a formula : The formula for the derangement can be used directly. The number of derangements is
  n!(12!−13!+14!+…+(−1)nn!)
  n!(12!−13!+14!+…+(−1)nn!)
  put the value of n and get your answer.
  
  i guess this is the fastest and safest way. hope it helpful. cheers.
• 8 years agoHelpfull: Yes(1) No(0)
• Hi friends. Is anybody here who got hall ticket and taken the tcs test today except karnataka state candidates.. Please tell me the difficulty level . :)
  
• 8 years agoHelpfull: Yes(0) No(1)
• 5 letters can be goes in different adress in 5! way and there is only condition in which it goes to proper adress so ans is 5!-1=119
• 8 years agoHelpfull: Yes(0) No(3)
• correct answer is 4^5/5^5=1024/3125
• 7 years agoHelpfull: Yes(0) No(1)
• Dearr(5) = 5! (1/0! - 1/1! + 1/2! - 1/3! + 1/4! - 1/5!)
  Dearr(5) = 120 (1 - 1 + 1/2 - 1/6 + 1/24 - 1/120)
  Dearr(5) = 60 - 20 + 5 - 1 = 44
• 4 years agoHelpfull: Yes(0) No(0)