Metlock, Inc. uses a periodic inventory system. Details for the inventory account for the month of January 2017 are as follows: Units Per unit price Total Balance, 1/1/2017 270 $5.0 $1350 Purchase, 1/15/2017 140 ..5 672 Purchase, 1/28/2017 140 ..5 700 An end of the month (1/31/2017) inventory showed that 220 units were on hand. How many units did the company sell during January 2017?