Chapter 4.4, Problem 59E

To determine

To choose: The flu is spreading at the rate of $\text{P}(t)=\frac{150}{1+e^{4-t}}$ , to find number of persons infected initially.

Answer to Problem 59E

Therefore,number of infected persons is $3$ and option (b) is correct.

Explanation of Solution

Given information: The given expression for spreading of flu at rate of,

  $\text{P}(t)=\frac{150}{1+e^{4-t}}$

Calculation: Using the differentiation,

  $\begin{array}{l}\text{y=P}(t)=\frac{150}{1+e^{4-t}}\\ \text{Putting t=0 intially for number of infected persons,}\\ \text{P(}0)=\frac{150}{1+e^4}\approx 2.7\\ \text{So, therefore intially number of infected persons is 3}\text{.}\end{array}$

So, therefore number of infectedpersons is $3$ and option (b) is correct.