Errol, a sole trader, finds that he has 1000 units of inventory at 30 November 2018. He had purchased 2500 units of this product at a price of $10. During the year he had sold 1500 units at $25 each. Out of the remaining, he discovered that 100 units had a net realisable value of only $15. What was the value of his inventory at 30 November 2018