Whenever graded schools can be made to accommodate the pupils of one or more one room schools by consolidating said one room school or schools with another school, either graded or ungraded, it shall be the duty of the board of school directors to abandon the one room school or schools, and instead of repairing or rebuilding the one room schoolhouse or schoolhouses, they shall erect a suitable modern building for the purpose of consolidating and properly grading all of the schools. No pupil of the abandoned schools shall be required to walk more than a mile and a half to the new school building.