Question

The internal and external diameter of a hollow hemispherical vessel is 20cm and 28cm respectively. Find the cost of painting the vessel allover at 40 paisa per cm square. (1)the external diameter of an iron pipe is 25cm and its length is 20cm, if the thickness of the pipe is 1cm, find the total surface of the pipe.

Answer 1

as the internal and external diameter is given so we can find the internet and the external radius then we will find the internal surface area and then the external surface area then which some both internal and external surface area so that we can find the total surface area of the figure then just divide the cost of per square metres that is 40 Paisa per square metre and then and then we will get the answer