The ledger of Carla Vista Company has the following work in process inventory account.

Production records show that there were $600$ units in the beginning inventory, $30\%$ complete, $1,800$ units started into production, and

$1,500$ units completed and transferred out. The beginning work in process had materials cost of $$3,040$ and conversion costs of $$750.$

The units in ending inventory were $40\%$ complete as to conversion costs. Materials are entered at the beginning of the painting

process, and conversion costs are incurred uniformly throughout the process.

$($a$)$

How many units are in process at May $31?$