What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

Three brothers Jacob, John, and James live in Mexico City. The product of the ages of these brothers is 175. Jacob and John are twins. How old is James?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

What does it mean?

A Child was born in Lahore, Pakistan.

Still child is not a Pakistani citizen.why ?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Sachin bought a car with a strange 5 digit numbered plate.The water image of the number is 78633 more than my car number. All the digits of car number are distinct.

What is the original number on number plate?