ab=12825/0.3=42750. This means b=42750/a so there are many values for b depending on what a is. So there are many solutions for a and b, an infinite number. Even if a and b are whole numbers there are still many solutions, because 42750 has many factors: 2, 3, 5, 6, 9, 10, 15, 18, 19, 25 and more. For example, if a=19, b=2250, if a=171, b=250, and so on.
Perhaps this question is part of a bigger question which limits the values of a and b?