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

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

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

Three people check into a hotel. They pay $60 for the rent of the room. After they check-in, the manager realize that the rent for the room is $55. So, he gives $5 to the bellboy and asks him to give it to them. The bellboy thinks that it will be difficult for the three people to share $5 among them and seeking the personal benefit, he pockets $2 and gives the remaining $3 to them.

Now, each person paid $20 and got back $1. In this manner, each of them paid just $19 which totals to the amount of $57. The bellboy has $2 with him and adding them, we get $59. So where is the remaining $1?

Two fathers and two sons decided to go to a shop and buy some sweets upon reaching. Each of them bought 1 kg of sweet. All of them returned home after some time and found out that they had 3kg of sweets with them.

They did not eat the sweets in the way, nor threw or lose anything. Then, how can this be possible?

What has a ring but no finger?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

Out of four images which one is the odd one out?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?