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

If 21x = 79x, what is the value of x?

Why is a river so rich ?

A father's child, a mother's child, yet no one's son.

Who am I?

On rolling two dices (six-sided normal dice) together, what is the probability that the first one comes up with a 2 and the second one comes up with a 5?

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?

Chef Andrea has to light the kitchen stoves to open her restaurant for the day. There are three stoves in the kitchen: A glass stove, a brick stove, and a wood stove. She only has one match. Which does she light up first?

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

What has many teeth, but cannot bite?

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?