Mix and Yield variance

Ques - Mr. Green makes salads.  The standard plate of salad has 30 g of lettuce (L), 50 g of peppers  (P) and 80 g of beetroot (B). The standard prices of the three ingredients are $0.2/kg,  0.4/kg and 0.8/kg respectively.  The actual prices were $0.22/kg, $0.38/kg and $0.82/kg.  Mr. Green has been experimenting and so in July he changed the mix of vegetables on the  plate thus: 1,500 plates contained 62,000 grams of lettuce, 81,000 grams of peppers and  102,000 grams of beetroot.  a) What is the cost difference between the actual mix and the standard mix to the nearest  cent?  b) What is the yield variance (do not round your answer)?  Answer : a) $11.41 b) 2.8125 A  My answer : a) 11412.5 b) -2812.5 My question : Sir , my answer is very similar in numbers I am not sure why it is showing 11.41 and 2.8125 , like is there any point in the question which I am missing on ? because the method is same and the answer is same its the decimal places which are changed.. Thanks in advance :)