Airtight Limited uses the weighted-average method in its process costing system. It manufactures a sealant that goes through three processing stages prior to completion. Information on work in the first department, Mixing, is given below for September:

Production data:
Units in process, 1 September; materials 100% complete; conversion 80% complete	15,000
Units started into production during September	90,000
Units completed and transferred out	?
Units in process, 31 September; materials 50% complete; conversion 30% complete	5,000
Cost data:
Work in process inventory, 1 September:
Materials cost	$38,250
Conversion cost	$33,000
Cost added during May:
Materials cost	$218,000
Conversion cost	$170,000

Required:

Answer the following questions:

1. Calculate the equivalent units of production for materials and conversion for September. (2 marks)
2. Calculate the cost per equivalent unit for materials and conversion for September. (1 mark)
3. Calculate the cost of ending work in process inventory in total for September. (1 mark)
4. What are the costs to be accounted for? (1 mark)