Why is it important to start with temporary investments that lead to permanent investments

The card shoppe needs to maintain 21 percent of its sales in net working capital. currently, the store is considering a four-year project that will increase sales from its current level of $349,000 to $408,000 the first year and to $414,000 a year for the following three years of the project. what amount should be included in the project analysis for net working capital in year 4 of the project?