Decision making-relevant cost: Illustration Ennerdale Ltd has been asked to quote a price for a one-off contract. The companys management accountant has asked for your advice on the relevant costs for the contract. The following information is available:

Materials The contract requires 3,000 kg of material K, which is a material used regularly by the company in other production.

The company has 2,000 kg of material K currently in stock which had been purchased last month for a total cost of $19,600. Since then the price per kilogram for material K has increased by 5%.

The contract also requires 200 kg of material L. There are 250 kg of material L in stock which are not required for normal production. This material originally cost a total of $3,125. If not used on this contract, the stock of material L would be sold for $11 per kg.

Labour The contract requires 800 hours of skilled labour. Skilled labour is paid $950 per hour. There is a shortage of skilled labour and all the available skilled labour is fully employed in the company in the manufacture of product P.

The following information relates to product P: $ per unit $ per unit Selling price 100 Less Skilled labour 38 Other variable costs 22 (60) 40 Required: (a) Prepare calculations showing the total relevant costs for making a decision about the contract in respect of the following cost elements:

(i) materials K and L; and

(ii) skilled labour.

(b) Explain the concept of opportunity cost.

(c) Explain the concept of non-relevant cost in decision making for managerial accounting.