The Lakeshore Hotels occupancy-days and custodial supplies expense over the last seven months were as follows:

Month	Occupancy-Days	Custodial Supplies Expense
March	18,050	$	9,800
April	12,540		9,850
May	15,060		13,700
June	28,650		16,000
July	24,300		17,520
August	17,000		13,250
September	14,600		12,990

Occupancy-days are a measure of the overall activity at the hotel. For example, when a guest stays at the hotel for three days, it is counted as three occupancy-days.

Required:

1. Using the high-low method, estimate a cost formula for custodial supplies expense.

2. Using the cost formula you derived above, what amount of custodial supplies expense would you expect to be incurred at an occupancy level of 13,200 occupancy-days?