How many words can a pen with half refill write?

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?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

A sundial has the fewest moving parts of any timepiece. Which has the most?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

A man is trapped in a room. The room has only two possible exits doors. Through the first door there is a room constructed from magnifying glass. The blazing hot sun instantly fries anything or anyone that enters. Through the second door there is a fire-breathing dragon. How does the man escape?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

Identify Me

Hint1: I am a god
Hint 2: I am a planet
Hint 3: measurer of heat

It spends most of its day eating white, but when it’s quick enough, it gets to eat fruit and sometimes some blue things. It’s in a dark room, where the walls are blue, it runs from a ghost that roams the halls and haunts it all the time. What is it?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?