Help please..!killing rate?

Question

in 2 seconds-estimated bacteria killed 14.98%

in 5 seconds-44.53%

the qn ask for the estimated exposure time needed to get 30%killing rate using data above?

should i put it as 5 seconds or is there calculations needed?

and what is cfu/ml of these..

10^-5 - 140 colonies

10^-6 - 74 colonies

10^-7 - 13 colonjies

Answer 1

30 is half way between 15 and 45. Assuming a linear killing rate, your answer will be half way between 2 and 5. I don't understand what you are asking in the second part.