Water is considered “safe to drink” when the bacteria population in the water is less than 75 parts per liter. “Treatment C” can kill bacteria at a rate of 11.5% per hour. If creek water is contaminated with a bacteria level of 1000 parts per liter, how long will it take to make the water safe to drink if treated with “Treatment C”?

The question is kind of confusing. if it's asking how many variations of answers can you give. then do 4^5 for your answer.this would be something like the first question could be a and the 2nd c or first b next c etc. if you can, ask the teacher for a better confirmation of what it's asking. if i'm assuming correctly what it's asking, it's 625 different variations.