In the answer for part b, it takes the standard quantity to be 24000 in its calculations but I think it should have been 20000 because budgeted production was 50000 cakes. Can you take a look please?
I assume that you are referring to the calculation of the yield variance.
We take the standard quantity (at standard mix) for the actual yield.
The actual yield was 21,600 kg of cake mixture and the standard quantity is 0.40kg for every 0.36 kg of cake mixture, Therefore the standard quantity for the actual yield is 0.40 x (21,600/0.36) = 24,000 kg