Can you place six X (crosses) in below board without making three in a row in any way ?

Can you count the number of seconds in a year?

Clue: You need to bother about calculation.

What country can make you shiver?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

A man lives on the fifteenth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator, or if it was raining that day, he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up five flights of stairs to his apartment. Can you explain why he does this?

Below, you can see three complete equations and one incomplete. Based on the three complete ones, can you complete the incomplete one?

5 $ 4 $ 3 $ 9 = 4215
6 $ 9 $ 2 $ 6 = 3816
4 $ 7 $ 3 $ 3 = 1122
7 $ 2 $ 7 $ 4 = ____