A cubical tank of side 10 m is open at the top. The inner surfaces of the tank including its base are to be painted at the rate of ₹5 per square metre. Find the total cost of painting.
₹2500
The tank is a cube of side \(a = 10\text{ m}\), open at the top, so the surfaces to be painted are the 4 vertical walls plus the base, i.e. 5 faces of the cube.
Area of one face \(= a^2 = 10^2 = 100\text{ m}^2\).
Total area to be painted \(= 5 \times 100 = 500\text{ m}^2\).
Total cost \(= 500 \times 5 = ₹2500\).
A solid cylinder has a radius of 7 cm and height of 10 cm. Find its total surface area. (Use \(\pi = \dfrac{22}{7}\))
A cube of side 6 cm is painted on all its faces and then cut into smaller cubes each of side 2 cm. Find the number of cubes which have exactly two faces painted.
A solid cylinder has a radius of 7 cm and height of 10 cm. Find its total surface area. (Use \(\pi = \dfrac{22}{7}\))