If 21x = 79x, what is the value of x?

Give it food and it will live; give it water and it will die.

I am lying and I always lie. Tell me whether I am lying or telling the truth.

John was running from 40 thieves. John has got 3 gold boxes which weigh as 4kg, 2kg, and 1kg respectively. A witty man asked John to stay with him for seven days in exchange for 1kg gold per day. John needs to stay there for seven days and also do not want to give the witty man any advance. How can John pay for his seven days stay?

In the picture given below, can you find out which digit will take place of the question mark?

Why do you find that most of the buildings are deprived of the 13th floor?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

What breaks yet never falls, and what falls yet never breaks?

A landlord calls both of his sons and tells them that their horses will now decide who will transfer the inheritance. He tells them to race along the land till the end and the one whose horse will be slower will win and be the heir to all the property.

Both of them keep wandering for days but to no result. Then they ask a wise man regarding it. The man advises them on the matter after which they jump on the horses and race as fast as they can till the end. Why did they do it?

What did the wise man say?

Kareena is older than Katrina and younger than Karishma. Isabelle is younger than Bipasha and Karishma. Bipasha is older than Karishma. If Kareena and Isabelle are the same age, who's the youngest?