How is this computed?

Department XY started the month with 1,000 units in work in process that were 100% complete as to materials and 70% complete as to conversion costs. During the month, 12,000 units were started, and 9,000 units were completed and transferred to Department ZT. The ending work in process units in Department XY are 100% complete as to materials and 40% complete as to conversion costs. Equivalent units of production for Department XY using FIFO costing equals Blank______.

Answer: 12,000 units for materials and 9,900 units for conversion costs