Question
Mathematics Question on permutations and combinations
If the four letter words (need not be meaningful ) are to be formed using the letters from the word "MEDITERRANEAN" such that the first letter is R and the fourth letter is E, then the total number of all such words is :
A
(2!)311!
B
110
C
56
D
59
Answer
59
Explanation
Solution
M, EEE, D. I, T, RR, AA, NN
R−−E
Two empty places can be filled with identical letters [EE, AA, NN] ⇒ 3 ways
Two empty places, can be filled with distinct letters [M, E, D, I, T, R, A, N] ⇒8P2
∴ Number of words 3+56=59
or
3+8P2=59