mix and yield varaince specimen exams sept.2016

To produce 19 literes of product x, standard input mix of 8 literes of chemical A and 12 literes of chemical B is required. Chemical A has a standard cost of $20 per liter and chemical B has a standard cost of $25 per liter.
During September, the actual results showed that 1,850literes of product x were produced, using a total input of 900literes of chemical A and 1,100 literes of chemical B.
The actual costs of chemical A and B were at the standard cost of $20 and $25 per liter respectively.
based on these information, which of the following statement is true

A both variances were adverse
B both variances were favorable
C The total mix variance was adverse and the total yield variance was favorable
D Total mix variance was favorable and total yield variance was adverse

Answer (D) but i did not know how they arrive at the figures with which they got this answwer .
AQSM of A 800 and for B was 1200 making total of 2000 for the material mix
Yield variance SQSM for A it was 779 and for B 1,168 making total of 1,947

I can calculate AQSM and AQAM but those above is my challenge , could you please, assisst on this?

Thanks in advance