12) What will be the rpm of smaller gear if a 180 mm dia meshes with 60 mm dia gear and the bigger gear makes 60 rpm?

13) What is the percentage of copper if the casting weight of copper 42.3 kg and tin weight 2.7 kg?

14) A motor cycle tyre is sold for Rs 300/- what is the purchase price if 25% profit is added to it.

15) What is the decimal fraction of conversion of 18.5%?