Since 1 US Dollar is equal to 2.0 Barbadian Dollars, we could say that n United States Dollars are equal to 2.0 times n Barbadian Dollars. In other words, we could use the following formula:
Barbadian Dollars = United States Dollars x 2.0
For example, let's say that we want to convert 2.0 United States Dollars to Barbadian Dollars. Then, we just replace United States Dollars in the abovementioned formula with 2.0:
Barbadian Dollars = 2.0 x 2.0
That is, 2.0 United States Dollars are equal to 4.0 Barbadian Dollars.