There are no given choices so I can't exactly answer this question. However, I can tell you the form of the probable answer to the choices that you have. When two variables have a direct relationship, the general formula would be: y = kx, where k is a constant. In this problem, the independent variable is number of hours, say t, so x= t. Consequently, y = earnings, say E. So, the answer would probably have the form of: E = kt, where k could be any real number.
