Every student receiving scholarships under the provisions of sections 160.276, 160.278, 160.281 and 160.283 shall teach in an elementary or secondary public school in this state for a period of five years after receiving a degree or the scholarship shall be treated as a loan to the student and interest at the rate of nine and one-half percent per year shall be charged upon the unpaid balance of the amount received from the date the student ceases to teach until the amount received is paid back to the state. In order to provide for the servicing of such loans, the department of elementary and secondary education may sell such loans to the higher education loan authority of the state of Missouri created under sections 173.350 to 173.450. For each year that the student teaches up to five years, one-fifth of the amount which was received under sections 160.276, 160.278, 160.281 and 160.283 shall be applied against the total amount received and shall not be subject to the repayment requirement of this section.