How many times can you subtract the number two from the number fifty?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

A man is found hanging dead from the ceiling of a room. The room’s dimensions are 15 x 15 x 15. The man is only 6ft tall and the rope was only 2ft long. There are no windows and only one door to the room. The door is bolted shut from the inside, and a puddle of water is under the man. How did he kill himself?

The following four words might seem abrupt to you. But you can make them meaningful by just adding vowels.
RDSH
GGPLNT
TMT
NN

Hint: All of them are vegetables.

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

Take one out and scratch my head, I am now black but once was red. What am I?

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.

But in the morning Christina finds out that each box still had three cupcakes. How?

Jenifer is learning to drive her car. She went down a one way lane and in the wrong direction. But she do not break any law.

How come ?