Consider the following network structure:

Assume that it is appropriate to keep $100$ inventory units at the plant warehouse. Show ALL work to determine:$$a$)$ the common days supply.$1000+(125+150+100)/(25+50+20)=1375/95=14\mathrm{.}47$ days$$b$)$ the amount allocated to each warehouse using the Fair Share Allocation method.

$1=(14\mathrm{.}47-125/25)$x$25=236\mathrm{.}75/237$ units

$2=(14\mathrm{.}47-150/50)$x$50=573\mathrm{.}5/574$ units

$3=(14\mathrm{.}47-100/20)$x$20=189\mathrm{.}4/189$ units

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$4)$ Analyze the following data to produce an ABC classification based on annual sales