List of top Mathematics Questions on Permutations asked in WBJEE

The number of ways in which the letter of the word 'VERTICAL' can be arranged without changing the order of the vowels is 

From a collection of $20$ consecutive natural numbers, four are selected such that they are not consecutive. The number of such selections is

The letters of the word COCHIN are permuted and all permutation are arranged in an alphabetical order as in an English dictionary. The number of words that appear before the word COCHIN is

Out of $7$ consonants and $4 $ vowels, the number of words (not necessarily meaningful) that can be made, each consisting of $3$ consonants and $2 $ vowels, is