Two machines, A and B, operate in some factory.
Machine A produces 10% of the factory's products.
Machine B produces 90% of the factory's products.
1% of machine A's products are flawed.
5% of machine B's products are flawed.
One product randomly selected.
what is the probability that it's flawed?
So, this is what I did:
Now, according to the law of total probability, we'll get that:
but the answer is:
Why were and omitted?