What always comes into a house through the keyhole?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

If you say my name, I will no longer exist. What am I?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

John can eat 27 chocolates in an hour, Jacob can eat 2 chocolates in 10 minutes, and Jolly can eat 7 chocolates in 20 minutes. How long will it take them to share and eat a box of 120 chocolates whilst playing Chess?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1000?

What is the next number in this matchsticks series riddle?

The chance of Mr John winning the lottery is 10%. All participants lined up and Mr John is 4th in the row. The first three participants lose the lottery.

What is the chance of Mr John now?

What does a man do only once in his lifetime, but women do once a year after they are 29?