Find the cost of painting a cuboid of dimensions 20 cm × 15 cm × 12

1.	Find the cost of painting a cuboid of dimensions 20 cm × 15 cm × 12 cm at the rate of 5 paisa per square centimeter.
Answer» l = 20cm, b = 15cm, h = 12cm. ∴ Total surface area of a cuboid A = 2(lb + bh + lh) =2(20 × 15 + 15 × 12 + 20 × 12) = 2(300 + 180 + 240) = 2 × 720 = 1440 sq.cm. The cost of painting a cuboid at the rate of 5 paisa per sq. cm for 1440 sq.cm. = 1440 × 5 paisa = 7200 paisa = ₹ 7200/100 = ₹ 72

Find the cost of painting a cuboid of dimensions 20 cm × 15 cm × 12 cm at the rate of 5 paisa per square centimeter.

Answer»

l = 20cm, b = 15cm, h = 12cm.

∴ Total surface area of a cuboid

A = 2(lb + bh + lh)

=2(20 × 15 + 15 × 12 + 20 × 12)

= 2(300 + 180 + 240)

= 2 × 720

= 1440 sq.cm.

The cost of painting a cuboid at the rate of 5 paisa per sq. cm for 1440 sq.cm.

= 1440 × 5 paisa

= 7200 paisa

= ₹ 7200/100

= ₹ 72