TipTop Flight School offers flying lessons at a small municipal airport. The school's owner and manager attempted to evaluate performance and control costs using a variance report comparing the planning budget to actual results. A recent variance report appears below:

After several months of using these reports, the owner has become frustrated. For example, she is confident instructor wages were very tightly controlled in July, but the report shows an unfavorable variance.

She developed the planning budget using the following formulas, where $q$ is the number of lessons sold:

$\backslash$table$[[$Revenue$,,$formas$],[$Instructor wages,,$$2409$