What does below rebus means ?

You are playing a game with your friend Jack. There are digits from 1 to 9. You both will take turn erasing one digit and adding it to your score. The first one to score 15 points will win the game.

Would you want to play first or second?

PS: The sum should be exactly 15.

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

When we see 2 but call 10?

Count the Triangle in the figure given below:

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

What makes this number unique: 8,549,176,320?

A pet show was happening in my locality. I went down along with my kids. In that show, I noticed that all except two of the entries were cats. All except two were dogs and all except two were Monkeys.

Can you find out how many of each animals were present in that pet show?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?