$(20$ points$)$ Volatile Industries originally estimated its annual demand for the TurboX$259$ as $800$ units per year and its holding costs for the same item as $\backslash (\backslash$$ $1\mathrm{.}00\backslash )$ annually. Volatile has discovered at the end of the year that annual demand is only $600$ units and holding costs per unit per year are closer to $\backslash (\backslash$$ $2\mathrm{.}00\backslash ).$ The only good news is that Volatile figured orders cost $\backslash (\backslash$$ $25\mathrm{.}00\backslash )$ to place when they really cost just $\backslash (\backslash$$ $20\mathrm{.}00\backslash )$ each. Volatile now wants to know the significance of these mistakes on last year's decisions. Conduct sensitivity analysis to determine the percent change of the errors on last year's decision.

a$.(5$ points$)$ What was the combined effect of these errors on the economic order quantity for the TurboX$250$ product? Express your answer as a percentage.

b$.(5$ points$)$ What was the individual effect of each error on the economic order quantity for this product? Express your answer as a percentage.

c$.(5$ points$)$ What was the combined effect of these errors on the total relevant costs for last year? Express your answer as a percentage.

d$.(5$ points$)$ What was the individual effect of each error on the minimum total relevant cost for last year? Express your answer as a percentage.