If n things are arranged in a row, the number of way in which they can be arranged so that non occupies its original position is `n!(1-(1)/(1!)+(1)/(2!)-(1)/(3!)+* * * + (-1)^(n)(1)/(n!))`
The number of ways of putting 6 letters into 6 addressed envelopes so that exactly 2 letters are in wrong is

If n things are arranged in a row, the number of way in which they can be arranged so that non occupies its original position is n!(1-(1)/(1!)+(1)/(2!)-(1)/(3!)+* * * + (-1)^(n)(1)/(n!)) The number of ways of putting at least 3 out of 6 letters in wrong envelops is

If n things are arranged in a row, the number of way in which they can be arranged so that non occupies its original position is n!(1-(1)/(1!)+(1)/(2!)-(1)/(3!)+* * * + (-1)^(n)(1)/(n!)) The number of ways of putting at least 3 out of 6 letters in wrong envelops is

If n things are arranged in a row, the number of way in which they can be arranged so that non occupies its original position is n!(1-(1)/(1!)+(1)/(2!)-(1)/(3!)+* * * + (-1)^(n)(1)/(n!)) Five boys are to be seated in a row. The number of ways in which 3 boys are not seated in the place specfied to them is

If n things are arranged in a row, the number of way in which they can be arranged so that non occupies its original position is n!(1-(1)/(1!)+(1)/(2!)-(1)/(3!)+* * * + (-1)^(n)(1)/(n!)) Five boys are to be seated in a row. The number of ways in which 3 boys are not seated in the place specfied to them is

If the number of ways in which 7 letters can be put in 7 envelopes such that exactly four letters are in wrong envelopes is N, then

If the number of ways in which 7 letters can be put in 7 envelopes such that exactly four letters are in wrong envelopes is N, then

The number of ways in which five different letters can be put in their five addressed envelopes so that all the letters are in the wrong envelopes is

The number of ways in which four letters can be put in four addressed envelops so that no letter goes into envelope meant for it is

Find the number of ways in which 4 letters can be put in 4 addressed envelopes so that no letter goes into the envelope meant for it.