The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

In the figure, you can see nine stars. What you have to do is connect all of them by using just four line and without lifting your hand i.e. in a continuous flow.

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Can you make a six-letter word using the letters N, A and B ?

What work can one never finish?

The day after tomorrow will be three days before Tuesday. Can you find out what is today?

Which is heavier: a ton of bricks or a ton of feathers?

What is harder to catch the faster you run?

John is selling fruits.
He sells grapes at $30, Dates $25, and a Wolfberry $45.
At what price does he sell fig?

PS: Logical Thinking

Suppose we lay down two cups in front of you. One of the cups is filled with tea and the other one with coffee. Now we ask you to take a spoonful of tea and mix it with the coffee. At this moment, the coffee cup has a mixture of tea and coffee. You have to take that mixture (spoonful) and add it back to the tea.

Can you now tell if the cup of coffee has more tea or the cup of tea has more coffee?