Adger Corporation is a service company that measures its output based on the number of customers served. The company provided the following fixed and variable cost estimates for budgeting purposes and the actual results for May as shown below: Revenue Employee salaries and wages Travel expenses Other expenses Fixed Element per Month Variable Element per Customer Served Actual Total for May $ 59,000 $ 38,000 $ 5,500 $ 2,000 $ 510 $ 204,000 $ 137,900 $ 17,500 $ 36,200 When preparing its planning budget, the company estimated it would serve 35 customers per month; however, during May the company actually served 40 customers. 6. What is Adger's revenue variance for May? Note: Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance). Input all amounts as positive values.