Using production and geological data, the management of an oil company estimates that oil will be pumped from a producing field at a rate given by the following. 90 t+9 R(t)= +9; Osts 15 R(t) is the rate of production (in thousands of barrels per year) t years after pumping begins. Find the area between the graph of R and the t-axis over the interval [7,12] and interpret the results.