Material Mix and Yield Variance

The following question is from BPP Mock Exam 1. The following cost information relates to product XY, which is produced in a continuous process from several different materials. ...................................................................................................................$ Actual quantity of materials at standard price......................................19960 Actual quantity of materials at actual price...........................................23120 Actual yield at standard materials cost.................................................20800 Standard yield from actual input of materials at standard cost...........19552 What is the materials yield variance for the period? A) $ 1248(F) B) $ 2320(A) C) $ 840(F) D) $ 3568(F) This is their explanation and answer. Correct Answer C Standard yield from actual input of materials at standard cost ..........$19552 Actual yield at standard materials cost ................................................$20800 Mix Variance (195520 - 20800) : $1248(F). There are typing errors. I know that "Standard yield from actual input of materials at standard cost" means "actual total input in standard mix at standard cost" but I don't understand "Actual yield at standard materials cost " Does it mean "standard input in standard mix at standard cost" Please, help me.