The supplies for the construction of a reinforced concrete building are supplied by the company a and b. The company a offers a 600 truck loads per day, while the company b offers 400 loads. Typically, 3% of the material of the company a will be of a lower quality, while 1% of the material of company b is deficient. A and B denote aggregates provided by the company a and b respectively.
The event E denote loads of inferior quality.
a) What is the probability that a supply is poor?
b) When a load supply is lacking, what is the probability that it is of the company a?