What is black when you buy it, red when you use it, and gray when you throw it away?

Move three sticks of the spiral below to form a square.

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

A man is found dead with a knife in his back When the investigation is done. A chair lays beside him and the forensic team finds moisture around the body.

If he committed suicide, how did he do it?

A Car is crossing a bridge 2 miles long. The bridge can only hold 10000 lbs, which is the exact weight of the car. The Car makes it half way across the bridge and stops. A bird lands on the car. Does the bridge collapse? Explain.

How many triangles can you find in this given picture?

When 99 is considered higher than 100?

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?

How many triangles can you count in the figure given?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?