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

What is more useful when it is broken?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

These types of puzzles are known as charades. What you have to do is find two words that are referred to in the first stanza and the second stanza and put them together to form the third word in the third stanza.

Just for example, if my first refers to 'off' and my second refers to 'ice', then my whole will be office.

My first is present - future's past -
A time in which your lot is cast.

My second is my first of space
Defining people's present place.

My whole describes a lack of site -
A place without length, breadth, or height.

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

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

What have one eye but still cannot see?