A solid metallic cone of base radius 6cm and height 18cm is completely melted. During melting, 5% of the metal is lost. The remaining metal is recast into small solid cones, each having base radius 3cm and height 2cm.
a. (i) Find the maximum number of small cones that can be obtained.
b. (ii) Calculate the volume of metal left unused after casting these small cones (give your answer in cm3 to two decimal places).