A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

I want to fill my bucket using both cold and hot water.
I have two taps for both cold and hot water. The hot water tap fills the bucket in exact 6 hours and the cold water tap fills the bucket in exact 4 hours.
I turn both of them simultaneously but I forgot to turn off another tap which removes the water out of the bucket. This tap can empty the bucket in 12 hours.

How Long will it take to fill the bucket?

There is something which you can be arrested for attempting but not for successfully completing.

Look at the picture and find out which square is not linked with any of the other squares.

The horse jumps over the king.
Strangely there is absolutely no scratch on him.

Can anyone explain, how is this possible?

81 x 9 = 801. What must you do to make the this equation true?

Count the number of triangles in the given picture.

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

When monkey rotate the gear, which mark will be hit 1 or 2 ?

I am a number I am not an odd number I am higher than 90 I am not higher than 100 If you subtract me from 100, you get nothing. What number am I?