Match the following

A blank of $$50$$ $$mm$$ diameter is to be sheared from a sheet of $$2.5$$ $$mm$$ thickness. The required radial clearance between the die and the punch is $$6\% $$ of sheet thickness. The punch and die diameter $$(mm)$$ for this blanking operation respectively are

Circular blanks of $$35$$ $$mm$$ diameter are punched from a steel sheet of $$2$$ $$mm$$ thickness. If the clearance per side between the punch and die is to be kept as $$40$$ microns, the sizes of punch and die should respectively be.

A gear with $$84$$ teeth is to be machined using a milling process with indexing. The index plate has the following four hole circles: $$36,38, 42., 48.$$ The change gear ratio required is