Given the data and information that follow, compute the total direct cost for each project duration.

If the indirect costs for each project duration are $$90(15-$time units$),$ $$70(14),$ $$50(13),$ $$40(12),$ and $$30(11),$ compute the total project cost for each duration. What is the optimum cost$-$time schedule for the project? What is the total cost?

Provide your answers demonstrating and explaining your calculations, schedules, and your assessment of your conclusion.