Answer:
10⁵(100,000)
Step-by-step explanation:
As given here, the initial population of bacteria was 10⁷( 10,000,000).
After the addition of antimicrobial chemical, the population of bacteria decreases at the rate of 90% of the total bacteria per 2 minutes,
So after 2 minutes the remaining bacteria is 10,000,000- 9,000,000= 1000,000( 10⁶)
So as in question, after next 2 minutes.
90% of this will die , so only 10% will remain= 1,000,000-900,000= 100,000
So After two minutes( total 4 minutes) the remaining bacteria is= 10⁵ (100,000)