A beautiful elegant of the (graph of this function is a straight line, which has a jump up by 0.06 at t equals 1500 minutes. The starting point of the straight line (at t equals 0) is (0,0), the slope of the first straight line is 0, since the basic fee of 15 is independent of the call duration. The slope of the second straight line is 0.06, since 6 cents are charged for each additional minute:1.3), by (Henri Matisse and Evelyn De Morgan:0.8), (Sfumato and Panorama:0.8), (painting:0.3) | Painting