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

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

The more of this there is, the less you see. What is it?

John, Jack and Jill are in a desert. John doesn't like Jill and hence decides to murder him. He poisons the water supply of Jill. Since it is a desert area, Jill must drink or he will die of thirst.

Jack does not know of the actions of John and also decides to murder Jill. To succeed in his ill motives, he removes the water supply of Jill so he dies of thirst.

Jill dies due to thirst. Who murdered Jill?

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

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?