managerial accounting help?

Foxworthy 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 July, the kennel budgeted for 2,000 tenant-days, but its actual level of activity was 2,050 tenant-days. The kennel has provided the following data concerning the formulas to be used in its budgeting:

Fixed Element per month variable element per tenant-day

revenue……………. ----- $32.90

wages and salaries……………… $2,900 $7.40

expendables…………………. 400 9.70

facility expenses…………. 9100 2.50

administrative expenses………. 7400 0.40

total expenses…………. $19,800 $20.00

The administrative expenses in the planning budget for July would be closest to:

$8,220

$8,200

$8,300

$8,098

could you please explain how you got your answer thanks !

Actual $7,400 + 2,050 x .40 = $8,220

Planned: $7,400 + 2,000 x.40 = $8,200