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

On a magical land of Mexico , all the animal in the land are rational.

There are 10 tigers and one goat.
Tiger can eat goat but since it's a magical land , the tiger who eats the goat , turns into goat and then can be eaten by the remaining tiger(s).

If we leave them for some time then how many goat and tiger will be there , when we come back ?

Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

What does below rebus means ?

Replace each alphabet with the number (1-9) to make the below equation correct.

AB * C = DE - F = GH / I

A man looks at a painting in a museum and says, “Brothers and sisters I have none, but that man’s father is my father’s son.” Who is in the painting?

Detective Rockford was jogging near the beach at 4:30 am.
He hears a sound near the shack "No Michael, Please Do not shoot me".
Next instance he heard the sound of gunfire. Rockford rushes to the shack where he finds women lying dead and a gun in close proximity of three "Doctore Lawyer and a Teacher".

Rockford immediately knew that the Lawyer has committed the crime. How?

What does it mean?

How can you make number one disappear by adding something to it?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?