epidemiology help! - calidoc4u

[ArchivalUser]

Kaplan question

55 yr old man visits his primary care with c/o of urinary infrequency. examination finds a 1cm nodule on his prostate gland. PSA is ordered. by common standards a level above 4ng/mL is considered abnormal. Using this standard, this test has sensitivity of 80% and specificity of 90%. a recently published article found that in a cross sectional study, 10% of men of this age have prostate cancer. the patient's result is 7ng/mL. what is your best estimate of the likelihood that this man has prostate cancer?
a. 13%
b. 25%
c. 36%
d. 47%
e. 58%
f. 69%
g. 72%



I have the answer but i have no idea how it was calculated. may someone please help explain how to approach it?!! epi isn't my best subjects

thanks in advance