Mix and Yield variance analysis-Lecture example -1 BPP notes

I have studied variance analysis in my graduation using formulas : Material Mix Variance : Standard cost for actual input - actual quantity at standard price Material Yield Variance : Standard cost for actual output - Standard cost for actual input. Using this formula when I do Lecture example-1 of BPP notes : Ques- Brenda and Eddie are analysing the main ingredients to their basic pasta sauce. The standard ingredients for one batch of tomato pasta sauce are: $ Onions 5kg @ $2/kg 10 Tomatoes 5kg @ $4/kg 20 30 During June, 100 batches of sauce were prepared, using the following ingredients: Onions 600 kg Tomatoes 900 kg For the total materials mix and total materials yield variance, was there a favourable or adverse result in June? I get mix variance correct but yield variance incorrect. Can you help me with my formula to solve this Question?