An open box is made of wood 3 cm thick. Its external length, breadth and height are 1.46m, 1.16m and 8.3dm respectively. What is the cost of painting the inner surface of the box at 50p per 100cm².
Answers
Answer:Given:
A open box is made of wood 3 cm thick its external length, breadth and height are 1.48 m , 1.16 m and 8.3 m.
To Find:
Find the cost of painting the inner surface at rupees 50 per square metre.
Solution:
Thickness of wood = t = 0.03 m
Internal length of box = L = External length - 2× Thickness of wood
Internal length of box = L = 1.48 - 0.03×2 = 1.42 m
Internal breadth of box = L = External breadth - 2× Thickness of wood
Internal breadth of box = B = 1.16 - 0.03×2 = 1.10 m
Internal height of box = L = External height - Thickness of wood
Internal height of box = H = 8.30 - 0.03 = 8.27 m
We know the formula of surface area of open box:
Surface area = 2 ×(L+B) ×H + L×B
Surface area = 2 ×(1.42+1.10) ×8.27 + 1.42×1.10
On solving:
Surface area = 43.2428 m²
Total cost of painting = Total area × price rate
Total cost of painting = 43.2428 × 50 = 2162.14 Rupees
Means total cost of painting the inner surface is 2162.14 rupees.
Step-by-step explanation: