4. (4 pts) Using estimates of rainfall, evaporation, and water consumption, the town engineer developed the following model of the water volume in the reservoir as a function of time: V(t)

= 10^9 + 10^8 (1 - e-t/100) - rt Write a function called reservoir (t) to compute the volume in the reservoir as a function of time. The function should have one argument, time. For r, user = 107 L/day. a. Plot the volume in the reservoir as a function of time (0 to 100 days; use r= 107 L/day). b. Use the Scipy fsolve function and your reservoir function to compute how long it will take until the reservoir is empty. Again, use a value of r = 107 L/day.