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

Which country gets ill every time?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

In the picture that is attached with this question, you can find a square which comprises of four little squares inside it. Consider this square to be made with matchsticks. You have to remove two matchsticks such that only two squares remain instead of five.How will you do it ?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

A large container is kept in open under the rain. Every passing hour, the water collected inside the container becomes double what it was.

In ten hours, the container is filled completely. Can you calculate how long would it have taken to be filled in half?

Give it food and it will live; give it water and it will die.

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

Rearrange the letters in "new door" to make one word.