Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

Can you place three balls such that the equation shown in the picture holds true?

If two fifty-foot ropes are suspended from a forty-foot ceiling that is twenty feet apart, how much rope will you be able to steal if you have a knife?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Jack and Joseph are well-known golf rivals. One Day during a match, they were level at a score of 30. Jack hit a bad shot and Joseph added 10 to his score. Joseph then hit an awesome shot and he won the game.

How ?

A sundial has the fewest moving parts of any timepiece. Which has the most?

What can go through glass without breaking it?

This is the oldest riddle that I have heard.

Once there was a man who was travelling with a Tiger, goat and grass.
He needs to cross a river that can carry a maximum of two i.e. Man + one of Tiger goat or grass. But the problem is "If he takes the lion with him, the goat will eat grass and if he takes grass with him, the lion will eat the goat".

How can he ensure the safe delivery of all three?

What is the riddle which can be asked all day with a different correct answer each time.

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?