WBCS (Executive) 2019 Prelims Previous Year Paper

In the following series, how many such odd numbers are there which are divisible by 3 or 5, then followed by odd numbers, and then also followed by even numbers?
$$\text{12, 19, 21, 3, 25, 18, 35, 20, 22, 21, 45, 46, 47, 48, 9, 50, 52, 54, 55, 56}$$

Consider the following arrangement:
$$\delta =\beta \text{ F 2 }\ast \text{ K S 7 5 }\#\$\text{ P L V S }@\text{ M U E 6 }\uparrow \text{ Q G }\text{c◯}\text{ 9 3 }\&\text{ T Y }\pounds$$

How many such letters are there in the arrangement each of which is either immediately preceded by a symbol or immediately followed by a number, but not both?

How many meaningful words can be made by changing only the consonants in the word MEAN so that each of the consonants is replaced by the previous letter in the English alphabet, by using each letter only once in each word?

If the first and third letters in the word NECESSARY were interchanged, also the fourth and the sixth letters, and the seventh and the ninth letters, which of the following would be the seventh letter from the left?

Arrange the following words according to dictionary arrangement:
(i) Epitaxy
(ii) Episode
(iii) Epigene
(iv) Epitome
(v) Epilogue