Final answer:
The correct mathematical representation of 'One scoop of rice weighs about 3⁹ milligrams' is expressed as 'y = 3⁹x', where 'y' is the weight in milligrams for 'x' number of scoops.
Step-by-step explanation:
The question relates to the concept of exponents in mathematics, particularly how to represent the weight of one scoop of rice as an exponential function of the number of scoops. The correct representation of the statement 'One scoop of rice weighs about 3⁹ milligrams' in a mathematical function is option a) y = 3⁹x, which means for every 'x' number of scoops, the weight 'y' in milligrams is '3⁹' times 'x'. Options b), c), and d) are incorrect because they suggest a different relationship between the number of scoops and the total weight where the exponent is incorrectly placed on the variable or the base.