Question:
The owner of a milk store finds that, he can sell $980$ litres of milk each week at $\mathrm{Rs}$ $14/\text{litre}$ and $1220$ litres of milk each week at $\mathrm{Rs}$ $16/\text{litre}$. Assuming a linear relationship between selling price and demand, how many litres could he sell weekly at $\mathrm{Rs}$ $17/\text{litre}$?