What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

What has a ring but no finger?

Which point will the car reach to go out?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.

What do you get if you add 2 to 100 four times?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

A deaf and mute man goes to the train station. Tickets for the train are 50 cents each. The man goes to the ticket booth and hands the man inside just a dollar. The man in the booth hands him two tickets.

How did the man in the booth know to give him two tickets without even looking at him?

I have an apple tree , number of apple in this tree get doubles every week.

On 30th week , the tree gets completely filled with apples :-)



Can you tell me , on what week does my tree is half covered with apples ?