If the government decides to provide public colleges, what tuition will these colleges charge to achieve the

Question:

If the government decides to provide public colleges, what tuition will these colleges charge to achieve the efficient number of students? How much will taxpayers have to pay?
The marginal cost of a college education is a constant $6,000 per student per year. The marginal external benefit from a college education is a constant $4,000 per student per year.