Which tank will fill first?

What does the below rebus riddle means?

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

*Hint: Check Puzzle Title

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

How many bananas can you eat if your stomach is empty?

Chocolate costs 6 rupees and a Toy costs 5 rupees. If you have 32 rupees in total, how many chocolates and how many Toys can be purchased with that amount?

We are a group of eight brothers. We consider the weak, yet we protect the king in every battle. If we move ahead, we never turn back. Who are we?

10+10 and 11+11 can give you the same answer.

Explain how?

Take one out and scratch my head, I am now black but once was red. What am I?