Answer:
On 11th day ( approx )
Step-by-step explanation:
Since, if a population change with a constant rate,
Then final population,
Where,
P = initial population,
r = rate of change per period,
t = number of periods,
Given,
Initial population = 2500,
Out of which, infected population = 30,
So, healthy people, initially = 2500 - 30 = 2470
Every day after, 18% of those still healthy fall ill.
So, after x days the number of healthy people,
Now, if 87% of 2470 are ill,
Then reaming healthy population = (100 - 87)% of 2470
= 13% of 2470
= 321.10
If P = 321.10,
From equation (1),
Hence, by 11 day at least 87% of the population be infected.