If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

If,

A + B = C
D - C = A
E - B = C

Based on the above equations, find out the answer for:

D + F = ?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

Open a Laptop which is password protected. Hint for the password is given as below:

1 mobile 3 books 2 Boards 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

Chef Andrea has to light the kitchen stoves to open her restaurant for the day. There are three stoves in the kitchen: A glass stove, a brick stove, and a wood stove. She only has one match. Which does she light up first?

After undergoing a successful eye operation, A blind girl has just boarded a train to her home. The doctor asked her to open the bandages after 3 hours. On her train journey, she opened the bandages and within a fraction of the time she commits suicide by jumping off the train.

Though her operation was successful, Why did she commit suicide?

I have an eye but still cannot see.

Who am I?