Calculate material mix variance using (1) Original Standard Mix Ratio (2) Revised Standard Mix Ratio:

For material A whose original standard consumption is 400 units at $12 as well as its actual consumption is 320 units at $ 13.

Similarly for material B whose original standard consumption is 200 units at $ 10 as well as its actual consumption is 280 units at $ 10.

It is decided to revise the standard consumption of material A to 340 and that of material B to 20 units to improve the quality of the product.