What is black when you buy it, red when you use it, and gray when you throw it away?

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different.

How do you measure 45 minutes?

Can you start the fire using two pieces of wood?

Identify The phrase in the picture.

What do you see in the image below

What does a man do only once in his lifetime, but women do once a year after they are 29?

What country can make you shiver?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

Can you circle exactly four of these numbers such that the total is twelve?

1 6 1
6 1 6
1 6 1
6 1 6