i need help understanding the steps

Vista Company manufactures electronic equipment. It currently purchases the special switches used in each of its products from an outside supplier. The supplier charges Vista $7.60 per switch. Vista's CEO is considering purchasing either machine A or machine B so the company can manufacture its own switches. The projected data are as follows: Required: 1. For each machine, what is the minimum number of switches that Vista must make annually for total costs to equal outside purchase cost? 2. What volume level would produce the same total costs regardless of the machine purchased? 3. What is the most profitable alternative for producing 285,000 switches per year and what is the total cost of that alternative