What always comes into a house through the keyhole?

Spot what is wrong here in below Picture?

I am white when I am dirty, and black when I am clean. What am I?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

Which word does the below Plexor means ?

What does it mean?

What has a ring but no finger?

If we tie a Sheep to one peg, a circled grass is been eaten by the Sheep. If we tie the Sheep to two pegs with a circle on its neck, then an eclipse is eaten out of the grass by the Sheep. If we want an eclipse then we put two pegs and then put a rope in between them and the other end of the rope is tied up on the Sheep's neck.

How should we tie the peg and the Sheep so that a square is eaten out from the garden grass? We only have one Sheep rope and the peg and the rings.

There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?