A cleaning company produces two sanitizer sprays. One spray kills 50% of germs, and another spray kills 25% of germs. However, 5% of the germs they kill are the same ones. What percentage of germs would be left after using both sanitizer sprays together? Let's be accurate as possible.
user
After the first spray kills 50% of germs, there will be 100 - 50 = 50% left. The second spray kills 25%, but 5% have already been killed by the 50% spray, so it kills 25 - 5 = 20%. After the second spray kills 20% of the remaining germs, there will be 50 - 20 = 30% left.
The answer: 30.
assistant