A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

Two boys were admitted to a school. When the headmaster asks them about their parents, they tell him that they have same parents (father and mother). On further inquiry, it turns out that they both share the same date for their birthday.

"Are you twins," ask the headmaster.
"No," replies the boys.

Is it possible?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

In the picture that is attached with this question, you can find a square which comprises of four little squares inside it. Consider this square to be made with matchsticks. You have to remove two matchsticks such that only two squares remain instead of five.How will you do it ?

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?