A chemist has 500 ml of a 30% acid solution. She adds x milliliters of a 10% acid solution. Which statement is true about the graph of the function that represents the concentration of the final solution?

Let y be concentration of the final solution:

y = (0.1x + 0.3 (500)) / (500 + x)

y = (0.1x + 150) / (500 + x)

The numerator contains the total amount of acid and the denominator contains the volume of the solution.