A grocery store wants to liquidate its stock of 10 apples, 20 bananas, and 80 grapes. Given past experience, the store knows that they can propose a banana-haters package with 6 apples and 30 grapes and that this package will bring a profit of six euros. Similarly, they can prepare a combo package with 5 apples, 6 bananas, and 20 grapes, yielding a profit of seven euros. They know they can sell any quantity of these two packages within the availability of its stock. What quantity of each package, banana-haters packages and combo packages, should the store prepare to maximize net profit?