(a) Given: Length of cuboidal box (l) = 60 cm

Breadth of cuboidal box (b) = 40 cm

Height of cuboidal box (h) = 50 cm

∴ Total surface area of cuboidal box = 2 (lb + bh + hl)

= 2 (60 × 40 + 40 × 50 + 50 × 60)

= 2 (2400 + 2000 + 3000)

= 2 × 7400 = 14800 cm²

(b) Given: Length of cubical box (l) = 50 cm

 Total surface area of cubical box= 6l²

= 6 × 50²

= 6 × 2500

= 15000 cm²

 Hence cuboidal box (a) requires the lesser amount of material to make since surface area of box (a) is less than that of box (b).