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

In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:

What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Oedipus solved the riddle, and the Sphinx destroyed herself.

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

Katniss and Peeta are liars. They both lie on some specific days.

Katniss lies on Fridays, Saturdays and Sundays. She speaks the truth on all other days.

Peeta lies on Tuesdays, Wednesdays and Thursdays. He speaks the truth on all other days.

Can you tell that one day of the week when both of them will say "Tomorrow, I will lie."?

A pregnant woman is preparing to name her seventh child. Her children's names so far are Dominique, Regis, Michelle, Fawn, Sophie, and Lara. What will she name her next child -- Jessica, Katie, Abby or Tilly?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?