Problem $19-16($Static$-$updated$)$

A garden store prepares various grades of pine bark for mulch: nuggets $($x$1),$ mini$-$nuggets $($x$2),$ and chips $($x$3).$ The process requires pine bark, machine time, labor time, and storage space. The following model has been developed.

Maximize $9$x$1+9$x$2+6$x$3($profit$)$

Subject to

Bark $5$x$1+6$x$2+3$x$3<=600$ pounds

Machine $2$x$1+4$x$2+5$x$3<=600$ minutes

Labor $2$x$1+4$x$2+3$x$3<=480$ hours

Storage $1$x$1+1$x$2+1$x$3<=150$ bags

x$1,$ x$2,$ x$3>=0$

a$-1.$ What is the shadow price of a pound of pine bark? $($Round your answer to $2$ decimal places.$)$