During a typical year, Mark's monthly sales compensation has ranged between $$14,000$ and $$18,800$ per month and units sold ranged

between $1,300$ and $2,100$ 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 $$143,400.$

Note: Round your "Commission rate" to $2$ decimal places.