What is the next number in this series?

4,12,84,3612....

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

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

Count the number of triangles in the given picture.

Can you decipher the following common phrase?

T M C
A U O
H S M
W T E

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?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

What do you get if you add 2 to 100 four times?

What is Luis Suarez's (Soccer Player) favorite tea?

It's a test that will check your IQ.

Suppose you have one 11 minute hourglass and one 13 minute hourglass.

Can you measure exactly fifteen minutes using them ?