A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

You Throw The Outside, Cook The Inside
Eat The Outside, Throw The Inside.

What Is It?

I make two people out of one. What am I?

You have two rectangular wires.

Both of them have property that when you light the fire from one end , it will take 60 minutes to get completely burn.

However, they do not burn at consistent speed (i.e it might be possible 1st 20% burn in 50 minutes and 80% can burn in 10 minutes).

So how could you measure 45 minutes ?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:

What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Oedipus solved the riddle, and the Sphinx destroyed herself.

What is the coolest letter in the alphabet?

If,

Akriti = 631
Levis = 521
Sroti = 521
Aneel = 533
Then,
Sunil =?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.