Number of ways in which 11 letters A,B,C,D,E,F,X,X,X,Y, Y can be arranged

The numbers of ways in which the letters of the word 'VOWEL' can be arranged so that the letters O, E occupy only even places is

Word of length 10 are formed using the letters A,B,C,D,E,F,G,H,I,J. Let x be the number of such words where no letter is repeated; and let y be the number of such words where exactly one letter is repeated twice and no other letter is repeated.The,(y)/(9x)=

Find the number of ways in which: (a)a selection (b) an arrangement,of four letters can be made from the letters of the word 'PROPORTION

The total number of ways of arranging the letters AAAA BBB CC D E F in a row such that letters C are separated from one another, is

In how many ways can the letters of the expressions x^(2)y^(3)z^(4) be arranged when written without using exponents?

How many arrangements of the 9 letters a, b, c, p, q, r, x, y, z are there such that y is between x and z? (Any two, or all three, of the letters x, y, z may not be consecutive.)

How many arrangements of the 9 letters a,b,c,p,q,r,x,y,z are there such that y is between x and z? (any two,are all three,of the letters x,y,z, may not be consecutive).