If the only perimeters are that the length has to be twice the width and less than 108 meters then there are an infinite amount of possible values for width. For example: 1.0002 and 2.0004 or 4 and 8. You can use an infinite amount of decimal places and therefore have an infinite amount of values.
The largest the width can be is the limit approaching 18 and it has to be greater than 0 tho