How many permutations can be formed from the letters in the word BOOKKEEPING

Question

using only 5 letters? 

 

 

Answer 1

Number of letters in the word BOOKKEEPING = 11.

There are three doubles and 5 singles.

We can take 3 cases to use 5 letters.

Case-1 Taking 2 doubles and 1 other.

Number of permutaions formed by 2doubles and 1 other

Case-2 Taking 1 double and 3 others.

Number of permutaions formed by 1double and 3 others

Case-3 Taking 5 others.

Number of permutaions formed by 5 distinct letters

Total number of perputations formed by using 5 letters of the word BOOKKEEPING is 540 + 6300 + 6720 = 13560.