Zk has been asked to quote a price for a special job that must be completed within one week. The job requires a total of $100$ skilled labour hours and $50$ unskilled labour hours. the current employees are paid a guaranteed minimum wage of khs$\mathrm{.}525$ for skilled workers and khs$\mathrm{.}280$ for unskilled workers for a $35-$hour week. Currently, skilled labour has spare capacity amounting to $75$ labour hours each week and unskilled labour has spare capacity amounting to $100$ labour hours each week. additional skilled workers and unskilled workers can be employed and paid by the hour at rates based on the wages paid to the current workers. The materials required for the job are currently held in inventory at a book value of khs$\mathrm{.}5,000.$ the materials are regularly used by zk and the current replacement cost for the materials is khs$\mathrm{.}4,500.$ the total scrap value of the materials is khs$\mathrm{.}1,000.$ What is the relevant cost to zk of using the materials in inventory$$on$$this$$job$?$