Question 25
A hand sanitizer kills 50% of the germs after one use and has the same effect on the surviving germs each time. Let $P$ be the percentage of germs killed after two applications. What is $100\times P$?
Clarification: in this expression, interpret $P$ as the decimal proportion killed (so 50% is written as 0.5). This is the convention used by the answer key.
Clarification: in this expression, interpret $P$ as the decimal proportion killed (so 50% is written as 0.5). This is the convention used by the answer key.