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?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

If 21x = 79x, what is the value of x?

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

Trying to tease Birbal, Akbar gave him one gold coin and ask him to buy
* something for him to eat
* something for him to drink.
* something to feed the cows
* something to plant in the garden
and most important you need to buy only one thing.

What must Birbal buy to silence Akbar?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

Two friends decide to get together; so they start riding bikes towards each other. They plan to meet halfway. Each is riding at 6 MPH. They live 36 miles apart. One of them has a pet carrier pigeon and it starts flying the instant the friends start traveling. The pigeon flies back and forth at 18 MPH between the 2 friends until the friends meet.

How many miles does the pigeon travel?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

what does the below rebus mean?