For the following exercises, use this scenario: Two different telephone carriers offer the following plans that a person is considering. Company A has a monthly fee of $\$ 20$ and charges of $\$ .05 / \mathrm{min}$ for calls. Company $\mathrm{B}$ has a monthly fee of $\$ 5$ and charges $\$ .10 / \mathrm{min}$ for calls.
Find the model of the total cost of Company As plan, using $m$ for the minutes.