Game of Maths

I’ve tried the game about telling the age, and here is the magic that I’ve found:

Let x be the number of times you eat out in a week,
Let y (year) be the year you are born, and
Let a (age) be your age.
 
According to the steps, the formular should be:

50(2x+5)+1757-y=100x+a
100x+250+1757-y=100x+a
100x-y+2007=100x+a
100x-100x-y+2007=a
2007-y=a   (see "x" is deleted)
 
Of course 2007(this year) – the year you are born = your age.

The same applies to those who haven’t had their birthday this year. (+1756)

So the game is actually a game of Maths and there is nothing to do with x.
Whether it means the numbers you eat out a week, or the number you take shower/use telephone/drink water a day, or your lucky number, or whatever. 

Next time when someone asks you to do a Maths question like this, never believe him coz he just wants to know your age.