Answer:
The function has a hole when x = 0 and a vertical asymptote when x = 4.
Step-by-step explanation:
Salt flows in at a rate of (5 g/L)*(3 L/min) = 15 g/min.
Salt flows out at a rate of (x/10 g/L)*(3 L/min) = 3x/10 g/min.
So the net flow rate of salt, given by
in grams, is governed by the differential equation,

which is linear. Move the
term to the right side, then multiply both sides by
:


Integrate both sides, then solve for
:


Since the tank starts with 5 g of salt at time
, we have


The time it takes for the tank to hold 20 g of salt is
such that

Check the picture below.
since the rectangular pool is a 14x30, the top and bottom part of that rectangle in the picture are just a 3x30 piece and the sides are 3x8, so how many ft² is that?
