A manufacturer obtains GPS systems from three different subcontractors: 20% from A, 45% from B, and 35% from C. The defective rates for the subcontractors are 1%, 3% and 2%, respectively.
a) Draw a Tree
b) What is the probability that a GPS system is defective?
c) If it is known that the GPS system is defective, what is the probability that it came from subcontractor B?