You have two buckets - one holds exactly 5 gallons and the other 3 gallons. How can you measure 4 gallons of water into the 5 gallon bucket?

(Assume you have an unlimited supply of water and that there are no measurement markings of any kind on the buckets.)

Find the next number in the series below

21 32 54 87 131 ?

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

Find the missing number in the series below

13 -21 34 -55 ? -144

Two friends were betting. One said to the other, "The coin will be flipped twenty times and each time the coin lands on the head, I will give you $2 and each time it lands on the tale, you will give me $3." After flipping the coin twenty times not a single penny was exchanged among them.

How many times did the coin land on heads?

I cannot talk, but I always reply when spoken to. What am I?

What country can make you shiver?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

You have three orange, two pink and five purple balls in the drawer beside your bed. There is no electricity and the room is entirely dark. How many balls must you take out to ensure at least one ball of each colour at least?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?