Suppose a person is having two surgeries performed at the same time. If the chances of success for surgery A are 85%, and the chances of success for surgery B are 90%, what are the chances that both would fail? What do you think of this solution: (.15)(.10) = .015 or 1.5%

The solution is both mathematically correct and appropriately solved.

The use of complementary events is incorrect.

The use of the general addition formula is incorrect.

The solution is mathematically correct, but just by luck...this is not the correct way to solve this question.

The solution assumes independence, which is most likely wrong.