During a typical year, Mark's monthly sales compensation has ranged between $17,500 and $23,700 per month and units sold ranged between 1,000 and 1,800 units for those same months. Required: Use the high-low method to determine Mark's monthly salary and commission rate per unit sold and then calculate the total number of units sold in a year when Mark's total compensation amounted to \$233,250. Note: Round your "Commission rate" to 2 decimal places