Q.

How many different words can be formed by jumbling the letters in the word MISSISSIPPI in which no two S are adjacent

1 7·C46·C48  
2 8·C46·C47  
3 6·7·C48  
4 6·8·C47  

Ans.

(1)

Leaving S, we have 7 letters M, I, I, I, P, P, I

Ways of arranging them =7!2! 4!=7·5·3

And four S can be put in 8 places in C48 ways.

Therefore, the required number of ways is =7·5·3·C48=7·C46·C48