Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

Two boys were admitted to a school. When the headmaster asks them about their parents, they tell him that they have same parents (father and mother). On further inquiry, it turns out that they both share the same date for their birthday.

"Are you twins," ask the headmaster.
"No," replies the boys.

Is it possible?

How many bananas can you eat if your stomach is empty?

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

You walk into a room where there are three primates held in their respective cages:
1) A lion who is eating the flesh of a goat.
2) An orangutan who is playing with blocks.
3) A donkey who is sitting idle.

Who is the most intelligent primate in the room?

What number do you get when you multiply all of the numbers on a telephone's number pad?

What occurs twice in a week, once in a year but never in a day?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.