The ratio table below describes the relationship between grapes and blueberries in a fruit salad.
Fruit Salad
Grapes (cups) Blueberries (cups)
2 1
4 2
20 10
24 12
Mandie is making 15 cups of fruit salad. What ratio of grapes to blueberries should she use?
6: 9
8: 7
10: 5
12:3