Adisease has hit a city. the percentage of the population infected t days after the disease arrives is approximated by p(t)equals=7 t e superscript negative t divided by 127te−t/12 for 0less than or equals≤tless than or equals≤4848. after how many days is the percentage of infected people a maximum

We have been given that function that models the population to be:
p(t)=7te^(-t/12)
we are required to compute for the time taken for the percentage of infected people to be maximum.
from the interval given, the maximum number will be at the point p'(t)
from the function;
p'(t)=-7/12e^(-t/12)(t-12)
equating this to zero and solving for t we get:
-7/12e^(-t/12)(t-12)=0
t=12
hence it will take a maximum of 12 days for infection to reach it's maximum percentage.

She will need 5/8 bags for each square yard.