I am eight letters long and am kept a secret from everyone. Letters two through four spell an animal, letters four to the end make a weapon, letters one, two and eight make what you use in an exam and my third and fourth letters are the same.
A password. You should keep your password a secret from everyone, letters two through four spell ass, an animal also known as a donkey. Letters four to the end spell sword, which is a deadly weapon and the letters one, two and eight make pad, which is used for writing during an exam. Lastly, the third and fourth letters are both ‘s’
A man wants to get into a night club where the bouncers test each person before they can enter. The man waits and watches. A woman walks up to the bouncers and the bouncers say 6. The woman replies with 3 and goes in. A small man walks up and they say 12. The man replies 6 and is admitted. The first guy thinks he’s figured it out and walks up. They say 4 and the man replies with 2, but they don’t let him in.
Pencil lead. While modern pencils don’t contain lead, that’s still what we call the graphite compound. When real lead was used in pencils it was mined and nearly everyone has used a pencil at some point in their life.
Someone bowled a strike. The ten white men are the pins, the dirt road is the bowling alley (it’s not dirt, but it’s the color of dirt, and if it said a smooth wooden alley it wouldn’t be much of a riddle). Three eyes as black as night are the finger holes in the bowling ball.