A sand with Gs = 2.66 and e = 0.60 is completely dry. It then becomes wetted by a rising groundwater table. Compute the unit weight (lb/ft³ or kN/m³) under the following conditions:

(a) When the sand is completely dry.

(b) When the sand is 40% saturated (S = 40%).

(c) When the sand is completely saturated.