You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

How can you tell a raw egg from a hard-boiled egg?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

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.

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

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

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

Through your logical capabilities, can you make 7 an even?