Rhed Kennel uses tenant$-$days as its measure of activity; an animal housed in the kennel for one day is counted as one tenant$-$day. During December, the kennel budgeted for $3,700$ tenant$-$days, but its actual level of activity was $3,650$ tenant$-$days. The kennel has provided the following data concerning the formulas used in its budgeting and its actual results for December:

Data used in budgeting:

$\backslash$table$[[,\backslash$table$[[$Fixed element$],[$per month$]],\backslash$table$[[$Variable element$],[$per tenant$-$day$]]],[$Revenue$,$$$0,$$$33\mathrm{.}90$