Carmen Co$.$ can further process Product J to produce Product D$.$ Product J is currently selling for $$20\mathrm{.}00$ per pound and costs $$15\mathrm{.}75$ per pound to produce. Product D would sell for $$38\mathrm{.}00$ per pound and would require an additional cost of $$8\mathrm{.}55$ per pound to produce.

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The differential cost of producing Product D is