In order to save energy and reduce emissions, hollow bricks are widely used in buildings to replace solid bricks. As shown in the figure, the specification of a hollow brick with a mass of 3.6kg is 20cm × 15cm × 10cm, and the solid part of the brick accounts for 60% of the total volume Find: (1) the density of the brick material; (2) How many kilos of material can be saved in the production of each hollow brick compared with the solid brick of the same specification?

In order to save energy and reduce emissions, hollow bricks are widely used in buildings to replace solid bricks. As shown in the figure, the specification of a hollow brick with a mass of 3.6kg is 20cm × 15cm × 10cm, and the solid part of the brick accounts for 60% of the total volume Find: (1) the density of the brick material; (2) How many kilos of material can be saved in the production of each hollow brick compared with the solid brick of the same specification?

V = 20cm × 15cm × 10cm * 60% = 3000cc * 60% = 1800cc = 1.8 × 10 ^ - 3M & sup3; P = m / v = 3.6kg/1.8 × 10 ^ - 3M & sup3; = 2 × 10 ^ - 3M & sup3; V '= 3000cc * (1-60%) = 1.2 × 10 ^ - 3M & sup3; m = PV = 2 × 10 ^ - 3M & sup3; × 1.2 × 10 ^ - 3M & sup3; = 2.4kg