Mix Variance/Yield Variance

Hi John,

I am stuck on a question. Please could you assist?

A product has a standard output of 32kg and a standard input of 8kg Input A and 32kg Input B

Input A has a standard cost of $10 per kg
Input B has a standard cost of $20 per kg

The actual output was 6400 kg using 900kg of Input A and 6100kg of Input B.

My answer

Mix Variance – Actual Mix

900 x 10 = 9000
6100 x 20 = 122000
7000kg – 131000

Std mix for total input
(8/40) x 7000) x 10 = 14000
(32/40) x 7000) x 20 = 112000
7000 kg – 126000

5000 adverse

Yield Variance
Std mix for total input
(8/40) x 7000) x 10 = 14000
(32/40) x 7000) x 20 = 112000
7000 kg – 126000

Std total input at std mix
(8/40 x 6400 ) x10 = 12800
(32/40 x 6400 ) x 20 = 102400
6400 kg – 115200

Surely it is 10,800 adverse? Answer is coming up as 18000 favourable