Answer:
1. How many will be infected next week
From the information, there are 1000 mice in the lab.
200 mice are infected. It is expected that 90% of the mice are expected to overcome the infection and 40% uninfected mice will be infected.
If 200 mice are infected, then number of uninfected mice is:
= 1000 - 200 = 800
90% of infected mice get cured. Out of 200 mice who are infected, the number of mice getting cures is:
N(E) = P(E)×N(S)
= 0.90*200
= 180
The number of mice still infected is 200 - 180 = 20
Out of 800 uninfected mice, 40% will get infected. Number of infected mice is:
N(E) = P(E) * N(S)
= 0.40 * 800
= 320
Total number of infected mice is 320 + 20 = 340
. Thus, the number of infected mice next week is 340
2. How many will be infected in 3 weeks
After three week, the number of infected mice is 340. Therefore, the number of uninfected mice is 1000 - 340 = 660
Now, out of 340 mice, it is expected that 90% will recover. This indicates that 10% will remain infected. Then the number of infected mice is
N(E) = P(E) * N(S)
= 0.10 * 340
= 34
Out of 660 mice, 40% will be infected. The number of mice becoming infected is
N(E) = P(E) * N(S)
= 0.40 * 660
= 264
Total number of infected mice is 264 + 34 =298. Thus, the number of infected mice after two weeks is 298.
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