During a year, Teri's monthly sales compensation ranged between $12,000 and $16,000 per month and units sold

Question:

During a year, Teri's monthly sales compensation ranged between $12,000 and $16,000 per month and units sold ranged between 1,600 and 2,400 units for those same months.

Required:
Use the high-low method to determine Teri's monthly salary and commission rate per unit sold and then calculate the total number of units sold in a year when Teri's total compensation amounted to $158,000.