Question

Find the cost of painting the total outer surface area of a box which is 60 cm long, 40 cm broad and 30 cm high at the rate of ₹1 per $10c{m}^2$ area.

• A. ₹1090
• B. ₹1070
• C. ₹1060
• D. ₹1080

Answer 1

The correct option is D ₹1080

Length of the box (l) = 60 cm.
Breadth of the box (b) = 40 cm
Hieght of the box (h) = 30 cm.

Total surface area of the box
= 2 (lb + bh + hl)
= 2( $60\times 40+40\times 30+60\times 30$) $c{m}^2$
= 2(2400 + 1200 + 1800)
= 2 × 5400 $c{m}^2$
= 10800 $c{m}^2$
Cost of painting 10 $c{m}^2$ area= ₹1.
Cost of painting 1 $c{m}^2$ area= ₹$\frac{1}{10}$.
Cost of painting 10800 $c{m}^2$ area
= ₹$\frac{1}{10}\times 10800$
= ₹1080