At the end of a snow storm, Luke saw there was a lot of snow on his front lawn. The temperature increased and the snow began to melt at a steady rate. There was a depth of 15 inches of snow on the lawn when the storm ended and then it started melting at a rate of 1.5 inches per hour. Make a table of values and then write an equation for S, in terms of t, representing the depth of snow on Luke's lawn, in inches, t hours after the snow stopped falling.