In calculating the amount of indebtedness to be assumed, any indebtedness authorized for the purchase or improvement of land or the erection, alteration, repair or furnishing of schoolhouses shall be included, whether incurred or not, and shall be treated as if the bonds or notes authorized to be issued to provide funds therefor had actually been issued, and the original cost of the acquisition or improvement so to be made shall be deemed to be the amount of indebtedness authorized for the making thereof.
N.J.S. § 18A:8-8