(a) The composition of a coal by mass is given as carbon 80%, hydrogen 5%, oxygen 6%, Nitrogen 2%, ash 5.5% and residual matter 1.5% Caiculate the higher and lower calorific values of the fuel. (b) An old waste vater distribution pipe of 250mm diameter of a chemical plant to be replaced by two paraliei pipes of smaller equal diameter having equal lengths and identical friction factor values. Find out the new diameter required [4+6=10]