Q:An electronic fuse is pro-duced by five production companies in a man-ufacturing operation. The fuses are costly, are

quite reliable, and are shipped to suppliers in

100-unit lots. Because testing is destructive,

most buyers of the fuses test only a small num-

ber of fuses before deciding to accept or reject

lots of incoming fuses.

All five production lines produce fuses at the

same rate and normally produce only 2% de-

fective fuses, which are dispersed randomly in

the output. Unfortunately, production line 1

suffered mechanical difficulty and produces 5%

defectives during the month of March. This

situation became known to the manufacturer

after the fuses had been shipped. A customer

received a lot produced in March and tested

three fuses. One failed. What is the probabil-

ity that the lot was produced by line 1? What

is the probability that the lot came from one

of the other four lines?

A:Clearly P (B) = 0.2

Then

P (A|B) = 3(0.05)(0.95)^2 = 0.135375.

Sorry for the weird formatting, I copy and pasted this question.

I don't see how they got this part...

P (A|B) = 3(0.05)(0.95)^2 = 0.135375.

The section this question is asked in goes over total probability and Baye's rule, but I can't seem to get that result ussing those techniques.

I just need help with this step, everything else should follow.