How do I approach SAT reading passages?

Lois and clark own a company that sells wagons. the amount they pay each of their sales employees (in dollars) is given by the expression 12h+30w12h+30w12, h, plus, 30, w where hhh is the number of hours worked and the number of wagons sold. what is the amount paid to an employee who works 666 hours and sells 333 wagons?