REM Manufacturing Co$.$ Ltd$.$ is designing an assembly line for the new product line. They want to produce $600$ items in a day. They plan to operate the facility $8$ hours a day. The design team gathered tasks, processing times, and sequence requirements shown below for optimization of the assembly line. No cellular layout will be used.

Tasks

Processing time $($sec$.)$

Immediate Predecessor$($s$)$

A

$20$

None

B

$25$

A

C

$15$

A

D

$30$

B

E

$20$

D

F

$35$

D

G

$30$

E

H

$27$

C$,$ F

I

$15$

G$,$ H