A word I know has six letters it contains, remove one letter and 12 remain. What is it?

You can hear me, but you can't touch or see me.

What am I?

Two natural numbers have a sum of less than 100 and are greater than one.

John knows the product of the numbers and Jacob knows the sum of numbers.

The following conversation takes place between them:
John: 'I am not aware of those numbers.'
Jacob: 'I knew you wouldn't be. I am not aware myself.'
John: 'Now I know them!'
Jacob: 'Now I know them, too!'

What are the two numbers?

When it's bad luck to meet a black cat?

Can you count the number of triangles in the picture below?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

Before Mount Everest was discovered, what was the highest mountain in the world?

What is the centre of gravity?

Solve the puzzle by telling what does below picture means.

In the image below, can you find the value of an angle(y)