Answer :

Let *L*1, *L*2, *L*3 be three letters and *E*1, *E*2, and *E*3 be their corresponding envelops respectively.

Let L_{i}E_{i} denote i^{th} letter is inserted in i^{th} envelope

∴ Sample space is

L_{1}E_{1}, L_{2}E_{3}, L_{3}E_{2},

L_{2}E_{2}, L_{1}E_{3}, L_{3}E_{1},

L_{3}E_{3}, L_{1}E_{2}, L_{2}E_{1},

L_{1}E_{1}, L_{2}E_{2}, L_{3}E_{3},

L_{1}E_{2}, L_{2}E_{3}, L_{3}E_{1},

L_{1}E_{3}, L_{2}E_{1}, L_{3}E_{2},

∴ there are 6 ways of inserting 3 letters in 3 envelops.

And there are 4 ways in which at least one letter is inserted in proper envelope. (first 4 rows of sample space)

Probability that at least one letter is inserted in proper envelope =

Rate this question :

Four candidates AMathematics - Exemplar

If A and B are muMathematics - Exemplar

State whethMathematics - Exemplar

If P (A ∪</Mathematics - Exemplar

State whethMathematics - Exemplar

If A and B are muMathematics - Exemplar

The probability tRS Aggarwal - Mathematics

In a town of 6000RS Aggarwal - Mathematics