- #1

opus

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**1. Homework Statement**

You’re testing the effect of a noxious substance on bacteria. Every 10 minutes, one-tenth of the bacteria which are still alive are killed. If the population of bacteria starts with 10^6, within which period of 10 minutes will 70% of the bacteria be killed?

## Homework Equations

N/A

## The Attempt at a Solution

I tried three different ways to solve, which are all on the attached image (seemed more effective to post that so you can see my reasoning). I’d just like to know if my equation set up is incorrect or if my calculations are incorrect. Each of the three attempts is in its own box. I know I’m wrong on all three, as the solution from the book says 110-120 minutes.