To determine how many cups of grapes are needed for 30 servings of fruit salad, first, we need to identify the number of cups of grapes required per serving.
The recipe calls for \( \frac{1}{4} \) cup of grapes for 4 servings. Therefore, for 1 serving, we divide \( \frac{1}{4} \) cup by 4:
\[ \text{Cups of grapes per serving} = \frac{1/4}{4} = \frac{1}{16} \text{ cup per serving} \]
Now, to find out how many cups of grapes are needed for 30 servings, we multiply the amount needed for one serving by 30:
\[ \text{Cups of grapes for 30 servings} = 30 \times \frac{1}{16} = \frac{30}{16} = \frac{15}{8} \text{ cups} \]
Converting \( \frac{15}{8} \) to a mixed number:
\[ \frac{15}{8} = 1 \frac{7}{8} \text{ cups} \]
Thus, you will need \( 1 \frac{7}{8} \) cups of grapes for 30 servings of fruit salad.