Approximately 25 % of American men in their 50's have prostate cancer. High levels of prostate specific antigens (PSA) in blood is used as a test for prostate cancer. Approximately 20% on men with prostate cancer have a normal PSA level and two out of three men without prostate cancer have high PSA levels. Calculate the probability that a PSA test on an American in his 50's will result in a false positive.