A factory which uses a large amount of coal is situated between two colliery X and Y, the former being 5 km and the latter 10 km distant from the factory. A fleet of lorries of 5 tonne carrying capacity is used for the collection of coal from the pitheads. The lorries average a speed of 20 km per hour when running and regularly take 10 minutes in the factory premises to unload. At colliery X loading time averages 30 minutes per load and at colliery Y 20 minutes per load.
Driver’s wages, licences, insurance, depreciation, garage and similar charges are noticed to cost Rs 6 per hour opened. Fuel, oil tyres repeats and similar changes are noticed to cost to paisa per kilometre run.
Recap a statement stating the cost per tonne kilometre of carrying coal from each colliery. If the coal is of equal, quality and price at pithead from which colliery should the purchases be made?