Current Attempt in Progr Waterway Company uses a periodic inventory system. Details for the inventory account for the month of January, 2020 are as follows: Per Units unit price Total Balance, 1/1/20 250 $4.00 $1000 Purchase, 1/15/20 100 5.40 540 Purchase, 1/28/20 100 5.70 570 An end of the month (1/31/20) inventory showed that 230 units were on hand. How many units did the company sell during January, 2020?