Find out the missing number in the picture attached:

What goes up but never comes down?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

A guard is positioned at the one side of the bridge saying ‘A’. His task is to shoot all those who try to leave from ‘A’ to the other side and say ‘B’. He also need to welcome the person who comes from another side ‘B’ to his side ‘A’. The guard comes out of his post every 1 hour and looks down the bridge for any people trying to leave. You are at side ‘A’ and wish to go to another side ‘B’. you also know that it would take 1:45 hr to cross the bridge. How will you cross the bridge?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

Our product and our sum always give the same answer. Who are we?

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?

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

I always drive my customer away.

Who am I?

Take away the whole and some still remain. What is it?