Which number should replace the question mark?

What has many keys but can’t open a single lock?

The peacock is a bird that does not lay eggs. How do they get baby peacocks?

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

Identify the movie name through below Rebus containing Pi Mouse and coconut tree..

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

You see me once in June, twice in November, and not at all in May. What am I?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

Your job is to measure 45 minutes if you have only two cords and matches to light the cords.

1. The two cords are twisted from various materials, so their different segments can burn at different rates.
2. Each cord burns from end to end in exactly one hour.

Describe your way of measuring the 45 minutes.