What is so fragile that saying its name breaks it?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

There are 4 big houses. They are made from the materials: red marble, green marble, white marble and blue marble.

* Mrs Jennifer's house is somewhere to the left of the green marble one and the third one alone is white marble.
* Mrs Sharon owns a red marbles house and Mr Cruz does not live at either end, but lives somewhere to the right of the blue marbles house.
* Mr Danny lives in the fourth house, while the first house is not made from red marble.

Who lives where, and what is their house made from?

It begins where the time ends.
Its second is an expression of surprise.
Its third is a question.
Its fourth is urinate.
It ends with a drink.

Which country it is?

There are three light switches outside a room. One of the switches is connected to a light bulb inside the room.
Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb?

John leaves home and then he takes three right turns. John wants to return to home but he was scared of Jacob, who is wearing a mask.

What is John Situation ?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

What type of tree can I carry in my hand?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?