Question

How many permutations can be made out of the letter of the word “COMPUTER”? How many of these (a) Begin with C (b) End with R (c) Begin with C and end with R? (d) C and R occupy the end places?

Answer 1

Answer:

Step-by-step explanation:

Here,total number of letter in a word "COMPUTER" are 8 .

so simply the total permutation is 8! i.e 40320

a) when begin with C then its be like C#######

  '#' could be any letter present in a word so the permutation is 1!*7!=5040

b) to end with R , its be like #######R

so permutation= 7!*1! =5040

c)When begin with C and end with R, C######R

 permutation= 1!*6!*1!= 720

d) C and R occupy end position in 2! ways and remaining 6 letters has the arrangement ways as 6! so,

Total number of arrangement =2!*6!

                                                 =1440