What is always in front of you but can’t be seen?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

Can you find out the missing number in the grid?

What is the word or phrase?

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

Alex opened 24 presents
Jonah opened 8 presents
Clara opened 1 present

Can you find out how many presents were opened by Candy?

That attorney is my brother, testified the accountant.

But the attorney testified he didn't have a brother.

Who is lying?

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?

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.

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS