5. (10 points) The economy on an island produces only grapes and wine. The production of 1 pound of grapes requires 42 pound of grapes, 1 worker, and no wine. The production of 1 liter of wine requires 1/2 pound of grapes, 1 worker, and 4 liter of wine. People on this island all together demand 1 pound of grapes and 3 liters of wine for their own consumption. How many workers needed so that this island can be self-sufficient