A courier company charges a fixed handling fee together with a charge that is proportional to the mass of the parcel. A 2 kg parcel costs Rs 180, while a 5 kg parcel costs Rs 300.
(i) Assuming the cost C (in rupees) varies linearly with mass m (in kilograms), obtain the linear equation connecting C and m.
(ii) Interpret the slope and the y-intercept of this equation in the given context.
(iii) Draw the graph of C against m for 0≤m≤8 kg.
(iv) Using the graph or otherwise, estimate the cost of sending a 7 kg parcel.
(v) For what mass will the cost be exactly Rs 240? Show the complete calculation.