The following consecutive readings were taken with a level and 4 m levelling staff on a continuously sloping ground at common intervals of 30 m. 0.905 (on A), 1.745, 2.345, 3.125, 3.725, 0.545, 1.390, 2.055, 2.955, 3.455, 0.595, 1.015, 1.850, 2.655, and 2.945 (on B). The RL of A was 395.500. Calculate the RLs of different points and find the gradient of the line AB.