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?

Find out the number of circles in the given picture having Illusion

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

I can be cracked, made, told, and played. What am I?

There are two insects on a tile. Insect X is sitting on one side of the tile (point A) and Insect Y is sitting opposite on the other side of the tile (point B). Now both of them decide to change their position and thus X starts crawling to point B and Y starts crawling to point A. When they meet and pass each other in between, X takes 20 seconds to reach B and Y takes just 5 seconds to reach A.

Can you calculate the total time each of the insects took to change their positions?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

A professor thinks of two consecutive numbers between 1 and 10.
'A' knows the 1st number and 'B' knows the second number

A: I do not know your number.
B: Nor do I know your number.
A: Now I know.

What are the four solutions for this?