which of the following could be used as a standard for a hotel in determining staffing variances? a.the average pay rate of housekeeping staff is $12 per hour. b.the number of guest rooms is 1,000. c.the average time it takes to clean a room is 42 minutes. d.both the average pay rate of $12 per hour and the average time of 42 minutes to clean a room could be used as standards.