Question

In a factory, producing parts for an automobile, the parts manufactured on the shop floor are required to go through three quality checks, each conducted after a specific part of the processing on the raw material is completed. Only parts that are not rejected at one stage are put through the subsequent stages of production and testing. If average rejection rates at these three testing machines during a month are 10%, 5% and 2% respectively, then what is the effective rejection rate for the whole plant?

• A. 17%
• B. 15.20%
• C. 84.80%
• D. 16.21%

Answer 1

The Correct Option is D

Successive rejection rate are 10%, 5% and 2% respectively.
Effective rejection rate after first two tests =\(10+5-(\frac{10\times5}{100})\)
\(=  15 −0.5 = 14.5\%\)
Similarly, effective rejection rate after third test =\(14.5+2-(\frac{14.5\times2}{100})\)
\(=  16.5 − 0.29 = 16.21\%\)
The correct answer is (D) :16.21%