A factory buys 7 machines. 2 MachineA, 4 MachineB and rest MachineC. Prices of the machines are Rs 56000, Rs 45000 and Rs 30000 respectively. Calculate the average cost of these machines.
A hollow hemispherical bowl is made of silver with its outer radius 8 cm and inner radius 4 cm respectively. The bowl is melted to form a solid right circular cone of radius 8 cm. The height of the cone formed is