Question: 1. If the price per tonne of steel is given by r, the price per hour of labour is given by w and the price per hour of machine time is given by m, then derive an expression for the total production costs of the firm in question 1 above.
2. The petrol consumption of your car is 12 miles per litre. Let x be the distance you travel in miles and p the price per litre of petrol in pence. Write expressions for
(a) the amount of petrol you use and
(b) your expenditure on petrol.