Given the function:
[tex]f(t)=\frac{A}{t+B}[/tex]
(a)
If t increases without bound, and given that A and B are constants, then the denominator increases without bound too. This means that the function decreases towards 0, then:
[tex]\lim _{t\to\infty}f(t)=0[/tex]
(b)
The y-intercept of the graph can be calculated for t = 0:
[tex]f(0)=\frac{A}{0+B}=\frac{A}{B}[/tex]
The coordinates of the y-intercept are:
[tex](0,\frac{A}{B})[/tex]
(c)
If the initial pressure (t = 0) is 35 psi:
[tex]\begin{gathered} f(0)=35 \\ \frac{A}{B}=35 \\ \Rightarrow A=35B \end{gathered}[/tex]
Now, if after 3 minutes the pressure is 29 psi:
[tex]\begin{gathered} f(3)=29 \\ \frac{35B}{3+B}=29 \\ 35B=87+29B \\ 6B=87 \\ \Rightarrow B=14.5 \end{gathered}[/tex]
Then:
[tex]\begin{gathered} A=35B=35\cdot14.5 \\ \Rightarrow A=507.5 \end{gathered}[/tex]
(d)
Finally, if f(t) = 14.74:
[tex]\begin{gathered} \frac{507.5}{t+14.5}=14.74 \\ 507.5=14.74t+213.73 \\ 14.74t=293.77 \\ \therefore t=19.930\text{ minutes} \end{gathered}[/tex]