Faith needs 4 cups of fruit for a smoothie.

She already has 78 cup of blueberries and 34 cup of oranges.

Drag the fruits Faith can use to make exactly 4 cups.

We have two fruits so we have following choices to make exactly 4 cups of fruits:

Blueberry Orange

0 4

1 3

2 2

3 1

4 0

In case 1: when she is using 4 cup of oranges so no need of blueberry.

In case 2: when she is taking 3 cup of oranges she will use 1 cup of blueberry to get exactly 4 cups of fruits.

case 3: when she is taking 2 cup of oranges she will use 2 cup of blueberries to get exactly 4 cups of fruits.

case 4: when she is taking 1 cup of orange she will use 3 cup of blueberries to get exactly 4 cups of fruits.

case 5: when she is taking 0 cup of orange she will use 4 cup of blueberries to get exactly 4 cups of fruits.