Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

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?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

I am the fastest animal but cannot climb the tree. What am I?

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 ?

The dirtier I get, the whiter I look. Who am I?

Begin with a word, five letters to my name,
Remove the first and last but I am the same
Take out my middle and still, I remain.
What word am I?