Question

In a workshop, three robots, Q, R and S, are employed to make chairs

 

Robot Q makes 25% of the chairs

Robot R makes 45% of the chairs

The remaining chairs are made by Robot S

 

Evidence has shown that 2 percent of the chairs made by robot Q are defective, 3 percent of the chairs made by robot R, and 5 percent of the chairs made by robot S are defective

 

(a) Construct a tree diagram that illustrates all possible outcomes and probabilities (5 marks)

 

Answer 1

percents of defective  chairs:

Robot Q: $0.25\cdot 0.02=0.005=0.5\%$

Robot R: $0.45\cdot 0.03=0.0135=1.35\%$

Robot S: $0.30\cdot 0.05=0.015=1.5\%$