SOLUTION:
Step 1:
In this question, we are given the following:
Step 2:
Part A:
The horizontal asymptote of the function is given as follows:

Part B:
With the use of the graphical calculator, the approximate time when the concentration is a maximum is:
From the graph, the approximate time when the concentration is a maximum is at:

Part C:
When is the concentration less than 0.345?
From the graph, the value of t when the concentration is less than 0.345 is at:
