At January 1, 2022, Juan, Inc. has begining inventory of 4,000 surfboards. Juan estimates it will sell 15,000 units during the first quarter of 2022 with a 10% increase in sales each quarter. Juan's policy is to maintain an ending inventory equal to 25% of the next quarter's sales. Each surfboard costs $200 and is sold for $250. How many units should Jake produce during the first quarter of 2022