We have the expression 12h+30w to represent an employees salary.
h represents the number of hours worked
w represents the number of wagons sold
To find the answer, simply insert the numbers given where their corresponding variables are in the expression.
12(6 hours) + 30(3 wagons)
(12*6) + (30*3)
72 + 90 = 162
So the employee earns $162