Final answer:
To determine the new ratio of roses to tulips after using half of each type of flower, we need to calculate how many tulips are left and the number of roses. With the given information, we cannot determine the new ratio.
Step-by-step explanation:
To determine the new ratio of roses to tulips, we first need to calculate how many tulips are left after using half of each type of flower to fill the order. Since the shop initially had 72 tulips, half of that is 36 tulips.
Next, we need to determine the new ratio of roses to tulips. If the number of tulips is 36, the ratio of roses to tulips would depend on the number of roses. Since the ratio is not provided in the question, we cannot determine the exact answer. Therefore, none of the answer choices (a. 12 roses and 24 tulips, b. 24 roses and 36 tulips, c. 30 roses and 40 tulips, d. 36 roses and 60 tulips) can be determined based on the given information.