Company A offers a starting salary of $28,000 with a raise of 3,000 each year. Company B offers a starting salary of $36,000 with a raise of $2,000 per year. Company C offers a starting salary of 18,000. After how many years would the salaries for Companies A and B be the same? How much of a raise per year would Company C have to offer to equal the salaries of Companies A and B in the year in which the salaries of those two are the same?