Can you name some countries which do not have the alphabet 'A' in them?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

How many times do a clock's hands overlap in a day ?

If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

How many times can you subtract the number 5 from 25?

If you say my name, I will no longer exist. What am I?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

Find the missing number in the image below.