I'm stuck on this question, please help:

Assume breast cancer affects 0.004 of the female population between 45 and 55 years of age.

There are two kinds of positive test results:

True positive (the test indicates you have a disease, and you actually have it)

False positive (the test indicates you have a disease, but you actually do not).

Assume mammograms are

0.90 accurate detecting people who actually have breast cancer (true positive rate)

0.91 accurate for people who do not have breast cancer (true negative rate).

******Must Compute the probability that a female between the ages of 45 and 55 who tests positive for breast cancer has breast cancer.****

******Some hints I received****

Bayes Theorem

Probability = desired event / all possibilities

In this case the desired event must be a true positive test.

All possibilities = true positive test + false positive test

Probability of a true cancer positive test = probability of having cancer * the probability that the test found the cancer.

The false positive = (1 - probability of having cancer) * the probability that the test found cancer (1 - true negative rate.)