let us consider there are four letters (L1,L2,L3,L4) with corresponding right addressed envelopes (e1,e2,e3,e4)

Now if we assume atleast one correct

Consider => L1-e1 is right => then L2 has 2 possible combinations such as e3 or e4 (we consider L2-e3); it cannot take e2 bcoz then there will be a combination with 2 letters in right envelop. Now the obvious choice for L3 to take e4 and not e3 (same logic for L2) and thus L4 is paired bydefault with e2.....Now plz refer below sequence with

2 possibilitiesHence =>

[L1-e1 | L2-e3 | L3-e4 | L4-e2] OR [L1-e1 | L2-e4 | L3-e2 | L4-e3]Now this sequence is only for L1-e1 to be the only right and all others are wrong; similarly

we have 4 pairs such as (L1-e1 | L2-e2 | L3-e3 | L4-e4 ) with 2 possibilities for eachHence Ans is 4 x 2 = 8 => 8/24 => 1/3...(plz let me know if i am right)

Plz consider for Kudos if right....(trying to access tests

)

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Bhushan S.

If you like my post....Consider it for Kudos