How many 5 letter words can be formed using letters in the word NIRMAL if (a) letters can be repeated (b) letters cannot be repeated

How many 4 letter words can be formed using letters in the word MADHURI if (a) letters can be repeated (b) letters cannot be repeated.

How many words can be formed by writing letters in the word CROWN in different order?

How many two letter words can be formed using letters from the word SPACE, when repetition of letters (i) is allowed, (ii) is not allowed?

How many three letter words can be formed using the letters of the word SQUARE? (Any arrangement of letters is called a word even though it may or may not have any meaning)

How many words can be formed from the letters of the word COURTESY, whose first letter is C and the last letter is Y?

Find the number of 4-digit numbers that can be formed using the digits 1, 2, 4, 5, 6, 8 if (a) digits can be repeated (b) digits cannot be repeated