An iron box with external dimensions 60 cm, 40 cm, and 20 cm is made of 1 cm thick sheet. If 1 cm³ of iron weighs 50 gm, the weight of the empty box is:

Given:

External dimensions of the iron box: 60 cm, 40 cm, and 20 cm

Thickness of the iron sheet: 1 cm

Weight of 1 cm³ of iron: 50 gm

Formula Used:

Volume of the box = External Volume - Internal Volume

Weight = Volume × Density

Calculation:

External Volume = 60 cm × 40 cm × 20 cm

External Volume = 48000 cm³

Internal dimensions: (60 - 2) cm, (40 - 2) cm, (20 - 2) cm

Internal Volume = 58 cm × 38 cm × 18 cm

Internal Volume = 39672 cm³

Volume of iron used = External Volume - Internal Volume

Volume of iron used = 48000 cm³ - 39672 cm³

Volume of iron used = 8328 cm³

Weight = Volume × Density

Weight = 8328 cm³ × 50 gm/cm³

Weight = 416400 gm

Weight in kg = 416400 gm / 1000

Weight in kg = 416.40 kg

The weight of the empty box is 416.40 kg.