If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

I look at you, you look at me, I raise my right, you raise your left. What am I?

Can you count the number of quadrilaterals in the picture below?

The host of a game show offers the guest a choice of three doors. Behind one is an 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?

Solve the mathematical equation in the picture below.

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

I shave every day, but my beard stays the same. What am I?

John is the son of Jacob.
So,
Jacob is the_____of John's father?