Kingsport Containers Company makes a single product that is subject to wide seasonal variations in demand. The company uses a job$-$order costing system and computes plantwide predetermined overhead rates on a quarterly basis using the number of units to be produced as the allocation base. Its estimated costs, by quarter, for the coming year are given below:

Quarter

First Second Third Fourth

Direct materials $ $280,000$ $ $140,000$ $ $70,000$ $ $210,000$

Direct labor $80,00040,00020,00060,000$

Manufacturing overhead $230,000206,000194,000?$

Total manufacturing costs $($a$)$ $ $590,000$ $ $386,000$ $ $284,000$ $ $?$

Number of units to be produced $($b$)80,00040,00020,00060,000$

Estimated unit product cost $($a$)-$: $($b$)$ $ $7\mathrm{.}38$ $ $9\mathrm{.}65$ $ $14\mathrm{.}20$ $ $?$