Answer:
a) 
Job          Direct Materials     Direct Labor     overhead         Total Job cost
Job 765               $6,160           $1,848              $3,366                 $11,374
Job 766               $10,944         $3,456             $9,792                $24,192
b)
For Job 765 = $86.167
For Job 765 = $126
Explanation:
Data provided in the question:
Job                 Direct Materials            Direct Labor          Machine Hours
Job 765               $6,160                         $1,848                      22
Job 766               $10,944                       $3,456                     64
Overhead rate = $153 per hour
Job 765 consisted = 132 units
766 consisted = 192 units
now,
Overhead = Machine Hours × Overhead rate
For Job 765 = 22 × 153
= $3366
For Job 766 = 64 × 153
= $9792
Total job cost i.e  balance on the job cost sheets
 = Direct Materials  + Direct Labor + overhead
a) 
Job          Direct Materials     Direct Labor     overhead         Total Job cost
Job 765               $6,160           $1,848              $3,366                 $11,374
Job 766               $10,944         $3,456             $9,792                $24,192
b)
Cost per unit = [ Total job cost ] ÷ Total units
For Job 765 = $11,374 ÷ 132
= $86.167
For Job 765 = $24,192 ÷ 192
= $126