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?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?

A kind heart person buy packed food at 3$/packet from United states and sells them at 1$/packet at Africa. After some time he becomes a millionaire.

How come the guy become millionaire ?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?