Each county director shall submit to the state director at such times as the latter shall require the director’s estimate of the necessary administrative expenses and expenditures in the county, which, when approved by the state director, shall be authority for the county director to engage such other agents and employees as may be necessary in executing the duties and activities delegated to the county director. All such agents and employees shall measure up to the standards fixed by the state director as to education, training, fitness and experience in social work.