Final answer:
Shirley should eat 3 cups of green beans.
Step-by-step explanation:
To find the number of cups of green beans Shirley should eat, we need to use the information that she wants to eat 2 times as many vegetables as she eats grains. Since she is eating 1.5 cups of brown rice (a grain), she needs to eat 2 times 1.5 cups of green beans. This can be represented by the equation: x = 2(1.5).
Simplifying this equation, we get: x = 3.
Therefore, Shirley should eat 3 cups of green beans