Question

A doctor recommends a two-step process to treat a rare form of pancreatic cancer. The first method is successful 80% of the time. If the first method is successful, the second method is successful 90% of the time. If the first treatment is not a success, the second is 25% of the time. What is the probability that only the second treatment is successful?

A. 5%
B. 8%
C. 20%

Answer 1

A. 5%

Explanation:

First treatment is successful (80% success rate), and second treatment is successful (90% success rate in this case).

Probability = 0.80 × 0.90 = 0.72 or 72% (success in both treatments).

First treatment is not successful (20% failure rate), and second treatment is successful (25% success rate in this case).

Probability = 0.20 × 0.25 = 0.05 or 5% (failure in the first treatment but success in the second).