This report identifies the longrun potential for savings available to Prince William County under an efficiently managed calendar of year round operations and specifies the areas in which these savings are most likely to occur. An analysis indicates that at the only secondary school in the County under the 45-15 plan, the overall 1971-72 per pupil cost of education was 9.6 percent lower than it would have been under a traditional 9-month calendar. The report provides a detailed breakdown of this reduction in cost. Results of the analysis lead to the conclusion that substantial savings are obtainable by districts which, like Prince William County, have management teams willing and able to make the necessary though sometimes difficult decisions involved in an innovative venture such as that of the 45-15 plan. (Author/JF)