Can you place six X (crosses) in below board without making three in a row in any way ?

In which direction should the missing arrow point?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

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

Can it be possible to build a house that has all its four walls facing towards the South?

How many letters are in the alphabet?

Can you find the ages of a son, father and grandfather based on the following facts?
The sum of the ages of grandfather, father and son is 140 years.
The age of the son in months is the same as the grandfather in years.
The age of the son in days is the same as the father in weeks.

What makes this number unique: 8,549,176,320?

A man lives on the fifteenth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator, or if it was raining that day, he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up five flights of stairs to his apartment. Can you explain why he does this?

Take away the whole and some still remain. What is it?