Answer: there are 70 cups of apples in the fruit salad.
Step-by-step explanation:
The ratio of oranges to grapes in the fruit salad is 5 cups to 6 cups. If the ratio of grapes to apples is 3 cups to 7 cups, it means that the ratio of oranges to apple in the fruit salad would be
5/6 × 3/7 = 5/14
Let x represent the number of cups of apples in the fruit salad. If there are 25 cups of oranges in the salad, it means that
25/x = 5/14
Cross multiplying, it becomes
x × 5 = 25 × 14
5x = 350
Dividing both sides by 5, it becomes
5x/5 = 350/5
x = 70