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 both treatments are unsuccessful?

Answer 1

Answer:

The answer is 15%.

Step-by-step explanation:

The probability that:

• Both treatments are successful:

       80% x 90% = 72%

• The first method is a success, but the second one is not:

        80% x (1 - 90%) = 8%

• The first method is not successful, but the second one is:

        (1 - 80%) x 25% = 5%

• Both treatments are unsuccessful:

        1 - (72% + 8% + 5%) = 15%