Convert 7.8.9.10.11.12.13.14.15 into factorial

How many numbers can be formed with digits 1,2,3,4,3,2,1 .So that odd digits always occupy the odd places?

The number of combinations of four letters taken word EXAMINATION.

In how many ways can 7 persons sit around a table.So that all shall not have the same neighbours in any two arrangements?

If nCr denotes the number of combinations of n things taken r at a time,then the expression n(r+1+n(r-1)+2*nCr equals

Suppose the word 'PENCIL' is given to us and we have to form words with the letters of this word,in how many ways we arrange if all words begin with a particular letters.

How many numbers of 3 digits can be formed with the digits 1,2,3,4,5 when digits may be repeated?

If nc₁₀ = nc₁₄,then 25 C_n =

If (n+1)! = 56 (n-1)!,then n=

The number of ways in which 10 different flowers can be strung to form a garland.So that 4 particular flowers are never separated.