Equipment A produces 12% and B produces 88% of spare parts.

Question

From the past, the company knows that the probability of equipment A to produce a defective spare part is 0.03 and the probability for equipment B to produce a defective spare part is 0.07. If a spare part is selected randomly from a daily output and is defective what is the probability that it was made by equipment B?

Answer 1

 

Hi Leva,

 

As the equipment A produces 12% of a daily output,

the probability that the equipment A generates a defective every day is

 

     0.03 · 0.12 = 0.0036.

 

As the equipment B produces 88% of a daily output,
the probability that the equipment B generates a defective every day is

 

     0.07 · 0.88 = 0.0616.

 

So, the answer is

 

     0.0616/(0.0036+0.0616) = 0.9448