Form sevenletter word by mixing up the letters in the word F
     Form seven-letter word by mixing up the letters in the word FIXTURE.  How many ways can you do this?  How many ways can you do this if all the vowels have to be at the beginning?  How many ways can you do this if no vowel is isolated between two consonants? 
  
  Solution
a>
Let say repeatition is not allowed then :
 the first place could be filled by 7 letters
 the second place could be filled by 6 letters
 and so on
 so total ways = 7*6*5*4*3*2*1 = 7! = 5040
b> in the word FIXTURE
 total vowels= {I , U , E}= 3
 total consonents = {F , x , T , R} = 4
if all the vowels need to be in the begining then
 the first three places would be filled in = 3*2*1 ways= 6 ways
 and the next four places would be filled by the consonents in = 4*3*2*1 = 24 ways
hence total ways = 6*24 = 144 ways

