What is the next number in this series?

4,12,84,3612....

If you read clockwise, you can form a word by inserting three missing letters in the picture given below. Can you do it?

Once upon a time, there was a castle on a square island. The entire island was surrounded by a 14m wide trench. The Romans had wanted to invade the castle and had brought a few wooden planks along with them to facilitate themselves in crossing the moat. The planks were however found to be only 13m long.

The Romans still managed to cross the trench. How did they do it?

John speaks the truth only once a day in a week. Below are a few hints for you:

First: Days are Sunday, Monday and so on.
Second: One day he says, "I lie on Monday and Tuesday".
Third: On the next day, he says, "Today is either Thursday, Saturday or Sunday".
Fourth: On the next day, he says, "I lie on Wednesday and Friday".

Can you identify the day on which he speaks the truth?

Prove that the below maths equation is true.

8 + 8 = 91

Which word does the below Plexor means ?

A man embarked on a questionnaire game. He kept asking the same question to whomever he found. The answer each time was different.

Can you guess what the question was?

I add 5 to 9 and get 2. The answer is correct, so what am I?

What is the Surname of Barbie Doll?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?