1. An electronics store is selling tablets and they have determined that their profit is given by
P(x) = 0.08x^2 + 80x, where x is the number of units produced and sold, and P(x) is given
in dollars.
Suppose that x is a function of time, in months, where x = 5t + 1.
a. Find the total profit as a function of time t.
b. Find the rate of change of total profit when t = 48 months.