the independent quantity is 12 per hr
the dependent quantity is 30 to 35 hrs
the domain is the x values and the range is the y values
y = 12x
y = 12(31) = 372
y = 12(32) = 384
y = 12(33) = 396
y = 12(34) = 408
so ur domain is { 31,32,33,34} and ur range is {372,384,396,408}