How many different four letter words can be formed (the words need not be meaningful) using the letters of the word "MEDITERRANEAN" such that the first letter is E and the last letter is R?
now simple condition E_ _ R
now there are two case
1st case
when repetaion is not allowed E _ _ R
1 2 3 4 (position of blank)
as letter need to be start by E so 1 st position can be filled in 1 way
as there are 13 letter in that word second position can be filled in 6 ways ( there are only 8 distinct letter and E has occupied first place and R occupies last place )
since repeatation not allowed of of letter 3 rd place can be filled in 5 ways (as 2 letter occupie first place)
as word need to end with R 4 th place can be filled in 1 way
so total number of word formed 6*5=30
second case ) repeatation is allowed
when repetaion is allowed E _ _ R
1 2 3 4
as letter need to be start by E so 1 st position can be filled in 1 way
as there are 13 letter in that word second position can be filled in 13 ways
since nothing said about repeatation of letter even 3 rd place can be filled in 13 ways
as word need to end with R 4 th place can be filled in 1 way
so total number of word formed 1*13*13*1 =169
check OA to find out what is asked i guess if not given anythin we go for repeatation
Ideation without execution is delusion
