Before Mount Everest was discovered, what was the highest mountain in the world?

What does this rebus means ?

PROG WORKRESS

In a football game, Christina defeated Teresa by 2 - 0 but no man from either side scored. How can this be possible?

What does does this rebus picture means ?

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.

When it's bad luck to meet a black cat?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

In my garden, I have many trees but only one of them is the mango tree. In these mango trees, there are some mangoes(as expected).

But after a strong wind, there are neither mangoes on the tree nor on the ground. Explain?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!