A factory produces three products P, Q and R. Each unit of each product requires time on Machine A, time on Machine B and a fixed quantity of raw material, as shown in the table below.
| Product | Machine A (hours) | Machine B (hours) | Raw material (kg) |
|---|---|---|---|
| P | 2 | 1 | 4 |
| Q | 3 | 2 | 1 |
| R | 5 | 4 | 2 |
On a particular day, the factory uses all of its available hours on Machine A, hours on Machine B and kg of raw material. Let , and denote the number of units of P, Q and R produced on that day.