Kubin Company$$s relevant range of production is $17,000$ to $26,500$ units. When it produces and sells $21,750$ units, its average costs per unit are as follows:

Average Cost per Unit

Direct materials $ $7\mathrm{.}80$

Direct labor $ $4\mathrm{.}80$

Variable manufacturing overhead $ $2\mathrm{.}30$

Fixed manufacturing overhead $ $5\mathrm{.}80$

Fixed selling expense $ $4\mathrm{.}30$

Fixed administrative expense $ $3\mathrm{.}30$

Sales commissions $ $1\mathrm{.}80$

Variable administrative expense $ $1\mathrm{.}30$

Required:

What is the incremental manufacturing cost incurred if the company increases production from $21,750$ to $21,751$ units?

What is the incremental cost incurred if the company increases production and sales from $21,750$ to $21,751$ units?

Assume Kubin Company produced $21,750$ units and expects to sell $21,470$ of them. If a new customer unexpectedly emerges and expresses interest in buying the $280$ extra units that have been produced by the company and would otherwise remain unsold, what is the incremental manufacturing cost per unit incurred to sell these units to the customer?

Assume Kubin Company produced $21,750$ units and expects to sell $21,470$ of them. If a new customer unexpectedly emerges and expresses interest in buying the $280$ extra units that have been produced by the company and would otherwise remain unsold, what incremental selling and administrative cost per unit is incurred to sell these units to the customer?