Core prints are provided to

A.Form trade mark of company on castings
B.Produce castings with specific surface design
C.Form seat to support and hold the core
D.Direct the flow of molten material during pouring
E.Reinforce the core to withstand the force of buoyancy of molten metal

In time study sone variations almost always occur from reading to reading for any element, even if the worker is not attempting to vary his pace. This variation is not caused by the following factors, among others

A.Random variations in operator movements and pace
B.Random variations in the positions of parts worked with
C.Random variations in the position of the tools used
D.Random variations caused by slight errors in watch reading
E.Random variations caused by electricity failures