Although the inspection system X and the inspection system Y are based on different principles, they can detect all product defects, and they will also mistakenly eliminate 3% of flawless products
Because the cost of error elimination is high, it would save more money by setting two systms at the same time and noly eliminating those which that both systems consider to be defective
The 3% flawless products eliminated by system X are not exactly the same as those eliminated by system Y.