The cylinders and pistons for the certain internal combustion engine are manufactured by a process that gives a normal distribution of cylinder diameters with a mean of 41.5 cm and a standard deviation of 0.4 com.
Similarly, the distribution of piston diameters is normal with a mean of 40.5 cm and a standard deviation of 0.3 cm.
If the piston diameter is greater than the cylinder diameter, the former can be reworked until the two "fit."
What proportion of cylinder-piston pairs will need to be reworked?