The graph below shows the solution to which system of inequalities?

2 × 3 = 6
3 × 3 = 9
4 × 3 = 12
Therefore, we know that there are 3x as many drops of colour as cups of frosting. If we look at point M, we see that there are 50 cups of frosting and 150 drops of colour. Since 50 × 3 = 150, point M is correct.
Point C, however, is incorrect, because there are 60 cups of frosting and 20 drops of colour, and 60 × 3 = 180, not 20.
The second answer is correct: point M, because there are 50 cups of frosting and 150 drops of colour.