A company that ships fruit has three kinds of fruit packs. The first pack consists of 10 oranges and 10 grapefruit, the second pack consists of 10 oranges, 15 grapefruit, and 10 apples, and the third pack consists of 5 oranges, 10 grapefruit, and 5 apples. How many of each pack can be made from a stock of 500 oranges, 750 grapefruit, and 300 apples?
10x+10y+5z <= 500
10x+15y+10z <= 750
10y+5z <= 300
or,
2x+2y+z <= 100
2x+3y+2z <= 150
2y+z <= 60
see what you can do with that