Nathan owns a trucking company. For each truck that goes out, Nathan must pay the driver $20 per hour of driving and also has to spend $2.75 per mile traveled on gas and maintenance. On one particular day, the driver drove an average of 30 miles per hour and Nathan's total expenses for the driver, gas, and truck maintenance were $820. He writes a system of equations that could be used to determine the number of hours the driver worked and the number of miles the truck traveled. He defines the variables that he uses to write the system. (Let's leave statements)