Since 1 US Dollar is equal to 81.512548 Indian Rupees, we could say that n United States Dollars are equal to 81.512548 times n Indian Rupees. In other words, we could use the following formula:
Indian Rupees = United States Dollars x 81.512548
For example, let's say that we want to convert 2 United States Dollars to Indian Rupees. Then, we just replace United States Dollars in the abovementioned formula with 2:
Indian Rupees = 2 x 81.512548
That is, 2 United States Dollars are equal to 163.025096 Indian Rupees.