What number do you get when you multiply all of the numbers on a telephone's number pad?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

A gardener planted the Lemon trees in a mathematical ordered way (i.e. he planted a tree in rows).
He created a total of 19 rows of trees.

Note: There should be more than 2 trees to count as a row.

What is the minimum number of trees required by the gardener to have 19 rows of trees?

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

Take one out and scratch my head, I am now black but once was red. What am I?

Find the missing number in the sequence below:

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

A man wants to cross the pit of fire which is 25 feet in length and he has 2 planks(fire resistant) 19 feet in length. How can he cross the pit of fire alive?