Note: answer this riddles and receive 3 Gold coins for each answer
Note: you will receive your gold coins immediately if you answer correctly, all this riddles contains 16 Gold coins, wishing you guys good luck, thanks

1-what can fill a room but takes up no space?
2-if a red house is made of red bricks and yellow house of yellow bricks, what of green house?
3-iam four times as old as my daughter , in 20 Years time i shall be twice as old as her. How old are we now?
4-what belongs to you but everyone else uses it?