Riyo Industries $,$;roduces heating equipment for ti$,$e months of December to March. The demand starls slow, peaks in the middle of the season, and tapers off toward the end. Because of the popularity of the product, the company may use overlime to satisfy the demand. The following table provides the production capacities nnd the de$111$a:$1$ds for thefour winter months.

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Unit production cost is Rs$\mathrm{.}12$ during regular time and Rs$\mathrm{.}18$ during overtime. The inventory carrying charge is $18\%$ perannum. Determine the optinrnl productionschedule.