What occurs twice in a week, once in a year but never in a day?

Can you circle exactly four of these numbers such that the total is twelve?

1 6 1
6 1 6
1 6 1
6 1 6

Can you find a five letter word that is left with only two letters if one is removed?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

You are trapped in a room with two doors. One leads to certain death and the other leads to freedom. You don't know which is which.
There are two robots guarding the doors. They will let you choose one door but upon doing so you must go through it.
You can, however, ask one robot one question. The problem is one robot always tells the truth, the other always lies and you don't know which is which.
What is the question you ask?

Find The Odd One Out

1. FLOW
2. SNIP
3. TRAP
4. DRAW
5. BACK

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

Before Balboa discovered the Pacific Ocean, which was the largest ocean before that?