Required information [The following information applies to the questions displayed below.] Frigid Supplies reported beginning inventory of 200 units, for a total cost of $2,000. The company had the following transactions during the month: January 3 sold 20 units on account at a selling price of $15 per unit. January 6 Bought 30 units on account at a cost of $10 per unit. January 16 sold 30 units on account at a selling price of $15 per unit. January 19 Sold 20 units on account at a selling price of $20 per unit. January 26 Bought 10 units on account at a cost of $10 per unit. January 31 Counted inventory and determined that 160 units were on hand. 3-a. What is the dollar amount of shrinkage that you were able to determine in periodic inventory system? 3-b. What is the dollar amount of shrinkage that you were able to determine in perpetual inventory system