Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

What runs around the whole yard without moving?

I have feet, but no legs. Which animal Am I?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

It's been the first day of the school when a young girl was found raped and murdered.
Police suspect four male teachers as on the killers and ask them what they were doing in the morning in time 8:00 am.
1. Wayne: I was reading the newspaper.
2. Terry: I was checking chemistry papers
3. Bridge: I had locked myself in my room as my wife left me.
4. Cole: I dropped my wife to her office.

Who is the killer?

There are four people in a house. A fireman, an athlete, an old woman, and a drunk guy. The house catches fire and before the fact is known, it is too late. All they know is that the entire house is in flames and it will collapse exactly after twelve minutes. Now they can move out of the house but for that, they will have to pass the hallway which is entirely blazing with flames. Thus to move, one must carry a fire extinguisher to keep the flames away. Seeking the burnt wooden floor, only two people can run through that hallway at one time. But for others to go, one must return back with the fire extinguisher. The fireman is trained for such tasks and can run through the hallway in a minute. The athlete can make it in a couple of minutes. The old woman can run slowly and will cover the hallway in four minutes. The drunk guy will take five minutes to run through it. If all of them can make it through the hallway in twelve minutes, all of them will be saved. When two move together, they will run at the speed of the slower ones.

How will all four of them manage to run to safety?

I am a five-letter word and people eat me. If you remove the first letter I become an energy form. If you remove the first two letters, I am needed to live. Scramble the last three letters and I am a drink. What word am I?

What has a bottom at the top?

What is the relationship between these matchstick pictures below?