Permutation of word with and without Repetition of letters.

[arpan20690]

How to deal with the questions where in a single word with two condition:
1. few letters without repetition.
2. Rest of the letters with repetition.
Example: find the no. of words u can form using the letters of word BELONG.
where first 3 letters without repetition and and last three letters with repetition.

[shankar.ashwin]

I am not sure what your doubt is,

but BELONG has 6 different letters, now different 6 letter word that can formed such that

first 3 letters without repetition and and last three letters with repetition would be

( _ _ _ ) ( _ _ _ ) = (6 * 5 * 4) * (3 * 3 * 3)

After the first 3 slots are filled in 6P3 ways, the remaining 3 letters can be used with repetition for the last 3 slots, so that is 3*3*3

[arpan20690]

But You are not mixing the two different kind of letters.