A company has four production sections S1, S2, S3 and S4 which contribute 30%, 20%, 28% and

Fantastic news! We've Found the answer you've been seeking!

Question:

A company has four production sections S1, S2, S3 and S4 which contribute 30%, 20%, 28% and 22% respectively to the total output. It was observed that these sections respectively produced 1%, 2%, 3% and
4% defective units.
Required:
What is the probability that the unit selected at random has come from either S? or S4.