there are 7372 people ahead of you
The first thing we will do is state the parameters we are given:
Your location is 2miles from the door.
Each person takes 18inches.
To know the number of people ahead, we will find how many inches make up a mile.
1 mile = 66360inches

Since 1 person = 18inches, the number of persons on that line would be:

There are 7373 people on the line.
The number of people ahead of you = 7373-1 = 7372
But, there are 7372 people ahead of you