the number of ways in which we can select five letters of the word intrenational is equal to ?

Dear manisha

here letters are  4 i  , 2 n  ,  f , t , e, s , m, a, l

case 1:  alll 5 are distinct

     number if words = ⁹C₅ 5!

case 2:  2 same and 3 distinct

        number of words =²C₁ * ⁸C₃ * 5!/2!

case 3 :  2 alike of one kind + 2 laike of one kind + 1 distinct

 number of words  = ²C₂ * ⁷C₁ *5!/2! 2!

case 4: 3 alike of one kind + 2 alike of other kind

    number of words = 1 *1 *5!/3!2!

case 5 : 3 alike of one kind and 2 distict

  number of words = 1 * 8C2 * 5!/3!

so add all above u will get the desired result

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