Why is it very easy to weigh a fish?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

What is the fastest way to double your money?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

I am eight letters long - "12345678"
My 1234 is an atmospheric condition.
My 34567 supports a plant.
My 4567 is too appropriate.
My 45 is a friendly thank-you.
My 678 is a man's name.

What word am I?

It belongs to you, but other people use it more than you do. What is it?

Your last good ping-pong ball fell into a narrow metal pipe embedded one foot deep in concrete.
How can you get it out undamaged, if all the tools you have are your tennis paddle, shoe laces, and plastic water bottle, which does not fit into the pipe?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

The centre of the third figure is empty. What digit should fit inside?