Quality assurance is an important aspect of any business. This case study is based on Lyman Limited, a

company that manufactures and sells office furniture. They obtain their parts (hinges, chair wheels, etc.) from

three different suppliers, A, B and C. Past experience has shown that 20% of the parts are supplied by A, 50%

are supplied by B and the rest are supplied by C. It is also known that 10% of the parts supplied by A are defect,

8% of the parts from B are defect and 6% of the parts from C are defect.

1.1 A part is randomly selected during a quality assurance test and is found to be defective. Calculate the

probability that it was supplied by supplier B.