Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

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

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

What type of tree can I carry in my hand?

A man was found murdered on Sunday morning. His wife immediately called the police. The police questioned the wife and staff and got these alibis: The Wife said she was sleeping. The Cook was cooking breakfast. The Gardener was picking vegetables. The Maid was getting the mail. The Butler was cleaning the closet. The police instantly arrested the murderer. Who did it and how did they know?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

You are playing as white and given four rooks to checkmate the black king in four moves with the following rules 1. You can place one rook every move and ensure the black king should be in check position.2. After four moves the black king should be in the checkmate position.

You know three triplets: Frank John and Wayne (need to return your money). Frank always tells the truth while John and Wayne always lie. You meet one of them on the road and can ask him a three-word question.
Which question, will you ask?

What's the only room from which no one can enter or leave