Find the cost of painting the outer surface of a hollow cylindrical pipe of radius 2 m andheight 21 m at the rate of ` 5 per m2.

Sure, here are the steps to find the cost of painting the outer surface of a hollow cylindrical pipe:

Step 1: First, we need to calculate the outer surface area of the cylindrical pipe. The formula for the surface area of a cylinder is 2πrh, where r is the radius and h is the height.

Step 2: Substitute the given values into the formula. The radius r is 2 m and the height h is 21 m. So, the surface area = 2 * π * 2 m * 21 m = 264 square meters.

Step 3: Now, we know that the cost of painting per square meter is ` 5. So, to find the total cost of painting, we multiply the surface area by the cost per square meter.

Step 4: The total cost of painting = 264 m^2 * 5 = 1320.

So, the cost of painting the outer surface of the hollow cylindrical pipe is ` 1320.