Hi,

I have a test tomorrow and I am really struggling with a question:

Suppose that among 100,000 women with negative mammograms, 20 will get breast cancer and that 1 woman in 10 with a positive mammogram will get breast cancer. Let A denote positive mammograms and B breast cancer. Find:

1. p(b|a(compliment))

2. p(b|a)

3. suppose that 7% of the general female population will have a positive mammogram. Find the probability of developing breast cancer among this female population.

I think i understand 1. and 2., would the first part just be 20/100,000 and would part 2 just be 1/10?

however i really don't get the last part?

Thanks