Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Buy me, smell me or deliver me, I do not change.

Who am I?

What does this say?

XLR8

What has many keys but can’t open a single lock?

John Went to the nearby store in a Mall to buy something for her home. Below is the conversation between the two:

John: How much for the one?
Shopkeeper: It is $2
John: How much for the Eleven?
Shopkeeper: It is $4
John: How much for the Hundred?
Shopkeeper: It is $6.

What is John buying?

They are three errirs in this question. Can you find them?

I travel all around the world but always stay in the corner. What am I?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

The Puzzle: Here is a famous prize problem that Sam Loyd issued in 1882, offering $1000 as a prize for the best answer showing how to arrange the seven figures and the eight 'dots' .4.5.6.7.8.9.0. which would add up to 82