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

Work in Process$-$Painting

$\backslash$table$[[\frac{5}{1},$Balance,$3,890,\frac{5}{31}$ Completed and transferred out $?],[\frac{5}{31},$Direct materials,$6,860,],[\frac{5}{31},$Direct labor,$3,066,],[\frac{5}{31},$Manufacturing overhead,$2,480,],[\frac{5}{31},$Balance,?,$]]$

Production records show that there were $600$ units in the beginning inventory, $30\%$ complete, $1,800$ units started into production, $1,500$ units completed and transferred out. The beginning work in process had materials cost of $$2,740$ and conversion costs of $$1,150.$ 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 $31?$

Work in process, May $31$

units