Count the number of triangles in the below picture?

Today, I celebrated my 32nd birthday but I was born in 1972.
How is this possible?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

I add 5 to 9 and get 2. The answer is correct, so what am I?

Name a key which is hardest to turn.

He digs out tiny caves and stores gold and silver in them. He also built bridges of silver and made crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs his help, yet many people are afraid to let him help them. Who is he?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

What does this rebus mean?

O
N
C
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TIME

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?

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?