Replace the question mark with the correct number in the below-given picture?

In the figure, you can see nine stars. What you have to do is connect all of them by using just four line and without lifting your hand i.e. in a continuous flow.

Can you tell a 3D object that has just two surfaces?

Katrina wants to go on a date and prefers her date to be tall, dark and handsome.

Of the preferred traits - tall, dark and handsome - no two of Shahrukh, Ajay, Salman and Akshay have the same number.
Only Shahrukh or Akshay is tall and fair.
Only Ajay or Salman is short and handsome.
Shahrukh and Salman are either both tall or short.
Ajay and Akshay are either both dark or both fair.
Who is Katrina's date?

Arrange the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 above and below the division line in a manner that the thus formed fractions equal to 1/3.

(You can use one number only once)

A few friends are enjoying their sea voyage in a boat full of apples. On the way, they felt hungry and thus decided to eat the apples. Together, they ate two dozen of apples. When they have eaten the apples, will there be any change in the water level?

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

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

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

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?