What are the next two letters in the following series and why? W A T N T L I T F S _ _

W hat a re t he n ext t wo l etters i n t he f ollowing s eries a nd w hy

Which means series contains the first letter of every word hence the last two letters are A & W

find the next number in following series: 16,21,26,26,12,??

Series: 2, 15, 13, 12, 12, 11, 11, ? Guess the ?

What is the next number in the series : 3, 24, 75, 175, 342, ?