Such an agreement shall provide that the state finance committee shall purchase, at par, warrants drawn upon the motor vehicle fund in payment for the property covered by the agreement and the engineering costs necessary for such advance purchase or condemnation. Such warrants shall be purchased by the state finance committee, upon the presentation by the holders thereof to the state treasurer, from any moneys available for investment in the state treasury as provided in RCW
43.84.080: PROVIDED, That in no event shall more than ten percent of the assets of any fund be used for the purpose of acquiring property as authorized herein, except in the case of current state funds in the state treasury, twenty percent of the balance therein available for investment may be invested as provided in RCW
47.12.180 through
47.12.240.