Replace the question mark with the number below given a simple math problem.

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

What is Luis Suarez's (Soccer Player) favorite tea?

How many triangles can you count in the figure given?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

How can you make number one disappear by adding something to it?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

There is a jar in which there are two types of candies.
20 blueberries and 16 strawberries. You perform the following steps:
1) You take out two candies.
2) If the two candies are of the same flavour, you add a blueberry one otherwise, you add the strawberry one.

You repeat these two steps till there is just one candy remaining in the jar. Which flavoured candy will be left?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?