A furniture dealer deals in only two items: tables and chairs. He has 5000Rwf to invest and a space to store at most (not more than) 60 pieces. A table costs him 250 Rwf and a chair, 50 Rwf. He can sell a table at a profit of 50 Rwf and a chair at a profit of 15 Rwf. Assuming that he can sell all the items that he buys, how should he invest his money in order that he may maximize his profit?